Home » Public Forums » GMCnet » Leaky brake fitting
| Leaky brake fitting [message #226316] |
Sun, 20 October 2013 19:05  |
Darryl
Messages: 144
Registered: December 2011
Location: Northern California
Karma: 0
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I've been fighting brake problems all summer. We had an issue on our first trip this year back in April so I decided to replace all the original hoses, the master cylinder and the combination valve. Everything seemed to work. Might have had a small leak but we weren't using it much. Then the new master cylinder went out. I replaced that and in the process I pulled off the combination valve so I could get enough leverage to properly seat the pigtail. Turns out no amount of leverage helps. The pigtail just sits on top but it seems to work so I reinstalled the combination valve but I couldn't get one of the 3/8 inch front brake line fittings tight enough to stop leaking. I eventually ended up rounding off the shoulders on the fitting with a pair of vice grips. So, I had a new brake line made up and bought a set of HF flair wrenches. I replaced the line yesterday but I still can't get it tight enough to stop leaking. I used the flair wrench and when it felt like it was going to slip I used a small pair of vice grips that hold the nut tight and that helped but the vice-grips were so small (it's a 3/8 fitting) I couldn't get enough pressure on it to do much good so I used the flair wrench again but with a pair of vice-grips over the end to keep it from spreading and that helped some but it eventually slipped. So, I'm beginning to think that if both the original fitting and the new one both leak when screwed into the same connection in the combination valve maybe the problem is the new (in May) combination valve. Does that make sense or should I just give up and take it to a brake shop?
We were going to leave Tuesday for a 2,500 mile trip but unless I can get this squared away we're not going anywhere for a while.
Darryl Meyers
1978 Eleganza II
El Dorado Hills, CA
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| Re: [GMCnet] Leaky brake fitting [message #226318 is a reply to message #226316] |
Sun, 20 October 2013 19:18  |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Darrel, the threads do not keep the brake fluid from leaking. The fit on
the flares is what seals. Carefully inspect with magnification, the flared
ends of the brake lines as well as the machined surfaces of the combination
valve where the tubing flare fits against it. I would suspect a split brake
line.
Jim Hupy
Salem, Or
78 Gmc Royale 403
On Oct 20, 2013 5:05 PM, "Darryl Meyers" <hospacctg@att.net> wrote:
>
>
> I've been fighting brake problems all summer. We had an issue on our
> first trip this year back in April so I decided to replace all the original
> hoses, the master cylinder and the combination valve. Everything seemed to
> work. Might have had a small leak but we weren't using it much. Then the
> new master cylinder went out. I replaced that and in the process I pulled
> off the combination valve so I could get enough leverage to properly seat
> the pigtail. Turns out no amount of leverage helps. The pigtail just sits
> on top but it seems to work so I reinstalled the combination valve but I
> couldn't get one of the 3/8 inch front brake line fittings tight enough to
> stop leaking. I eventually ended up rounding off the shoulders on the
> fitting with a pair of vice grips. So, I had a new brake line made up and
> bought a set of HF flair wrenches. I replaced the line yesterday but I
> still can't get it tight enough to stop leaking. I used the flair wrench
> and when it felt like it was
> going to slip I used a small pair of vice grips that hold the nut tight
> and that helped but the vice-grips were so small (it's a 3/8 fitting) I
> couldn't get enough pressure on it to do much good so I used the flair
> wrench again but with a pair of vice-grips over the end to keep it from
> spreading and that helped some but it eventually slipped. So, I'm
> beginning to think that if both the original fitting and the new one both
> leak when screwed into the same connection in the combination valve maybe
> the problem is the new (in May) combination valve. Does that make sense or
> should I just give up and take it to a brake shop?
>
> We were going to leave Tuesday for a 2,500 mile trip but unless I can get
> this squared away we're not going anywhere for a while.
> --
> Darryl Meyers
>
> 1978 Eleganza II
>
> El Dorado Hills, CA
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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| Re: Leaky brake fitting [message #226327 is a reply to message #226316] |
Sun, 20 October 2013 20:31 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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for what it is worth....
I thought I had a issue with a brake line leaking on that valve as well. replaced the line, and it still leaked.
well, it turned out it was the button or place to hook up the light, on the front of the valve. hit that with a wrench, gave it a snug, and no more leaks.
it was dripping down on that front brake line. and even though I hit it with brake cleaner, I just did not see it well enough to tell it was not from that brake line. I was pretty convinced at the time it was the brake line.
my next thing I was going to try is called a "flare saver" little brass washer. I now have a bag of them in the garage since i did not use them.
bought them from this company, they showed up within a week:
http://dmpfasteners.com/shop/an-fittings-and-hose-1647/tubing-1003/copper-flare-saver-1005/
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: Leaky brake fitting [message #226328 is a reply to message #226316] |
Sun, 20 October 2013 20:40 |
Otterwan
Messages: 946
Registered: July 2013
Location: Lynnwood (north of Seattl...
Karma: 0
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| Darryl wrote on Sun, 20 October 2013 17:05 |
I've been fighting brake problems all summer. We had an issue on our first trip this year back in April so I decided to replace all the original hoses, the master cylinder and the combination valve. Everything seemed to work. Might have had a small leak but we weren't using it much. Then the new master cylinder went out. I replaced that and in the process I pulled off the combination valve so I could get enough leverage to properly seat the pigtail. Turns out no amount of leverage helps. The pigtail just sits on top but it seems to work so I reinstalled the combination valve but I couldn't get one of the 3/8 inch front brake line fittings tight enough to stop leaking. I eventually ended up rounding off the shoulders on the fitting with a pair of vice grips. So, I had a new brake line made up and bought a set of HF flair wrenches. I replaced the line yesterday but I still can't get it tight enough to stop leaking. I used the flair wrench and when it felt like it was going to slip I used a small pair of vice grips that hold the nut tight and that helped but the vice-grips were so small (it's a 3/8 fitting) I couldn't get enough pressure on it to do much good so I used the flair wrench again but with a pair of vice-grips over the end to keep it from spreading and that helped some but it eventually slipped. So, I'm beginning to think that if both the original fitting and the new one both leak when screwed into the same connection in the combination valve maybe the problem is the new (in May) combination valve. Does that make sense or should I just give up and take it to a brake shop?
We were going to leave Tuesday for a 2,500 mile trip but unless I can get this squared away we're not going anywhere for a while.
|
First, Harbor Freight flare wrenches are crap. You might be able to use them if you clamp a pair of vice grips across the end the keep them from spreading, but I'd recommend getting a name brand set.
Second, if you've already messed up the nut, get a Vice-Grip nut plier:
http://www.amazon.com/Vise-Grip-Locking-Wrench-With-Cutter/dp/B00004SBBD/ref=wl_it_dp_o_pC_nS_nC_qpt2?ie=UTF8&colid=11XIQDLBDP0U6&coliid=I2JFB C6DVC2JQA
These will move most stubborn nuts without damaged them.
Finally, if you are having this much trouble installing the fitting, I would begin to suspect something else is wrong. Most brake fittings can be started by hand. If yours can't, make sure the nut and thread match and neither is damaged.
1977 Birchaven, Lynnwood WA - "We may not be able to stop all evil in the world, but I know that how we treat one another is entirely up to us."
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| Re: Leaky brake fitting [message #226329 is a reply to message #226316] |
Sun, 20 October 2013 20:43 |
Darryl
Messages: 144
Registered: December 2011
Location: Northern California
Karma: 0
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Senior Member |
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Jim
I've had two separate lines, the original and the new one I had made up, that both leak. I'll have another line made up tomorrow but is it possible the fitting on the combination valve is the problem?
Darryl Meyers
1978 Eleganza II
El Dorado Hills, CA
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| Re: Leaky brake fitting [message #226330 is a reply to message #226327] |
Sun, 20 October 2013 20:46 |
Darryl
Messages: 144
Registered: December 2011
Location: Northern California
Karma: 0
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Jon
Thanks for a new apparoach. Eveything I have read so far says to just tighten it more and eventually you'll get the leak to stop.
Darryl Meyers
1978 Eleganza II
El Dorado Hills, CA
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| Re: [GMCnet] Leaky brake fitting [message #226334 is a reply to message #226329] |
Sun, 20 October 2013 20:56 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Yes, do you have the brass valve, or a cast iron one. Leaky fittings are a
pita. I was changing a combination valve out today, and I had to cut off 3
out of the 5. And that was after a 2 day wait with penetrating oil. Kills a
good attitude quick. Remember this, new is just new, not necessarily good.
If the threaded holes run out of threads before the bottom of the bore, the
threaded nut will bind up before there is enough clamping force to seal the
flares. Make sure that the flared end of the lines extends past then of the
nut. If they do not, they will leak for sure.
Jim Hupy
Salem, Or
78 Gmc Royale 403
On Oct 20, 2013 6:43 PM, "Darryl Meyers" <hospacctg@att.net> wrote:
>
>
> Jim
>
> I've had two separate lines, the original and the new one I had made up,
> that both leak. I'll have another line made up tomorrow but is it possible
> the fitting on the combination valve is the problem?
> --
> Darryl Meyers
>
> 1978 Eleganza II
>
> El Dorado Hills, CA
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: Leaky brake fitting [message #226338 is a reply to message #226328] |
Sun, 20 October 2013 21:51 |
Darryl
Messages: 144
Registered: December 2011
Location: Northern California
Karma: 0
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David
I agree that HF tools are not optimal but the flair wrenches have to be better than the open-end wrench I first used. I did put a pair of vice grips on the end to stop the spreading and it helped but eventually it slipped and rounded the shoulders. I'd get a name-brand tool but I hope never to have to do this job again.
I have a couple of the vice-grip nut-pliers. They work pretty well so long as you are very careful to get the plier oriented properly before you lock it and apply any torque. Sometimes hard to do when you can't see what you are doing. The larger of the pliers I have won't grip the 3/8 fitting tightly and the smaller one is so small that I can't get much torque on it as I have to use it on the back side of the combo valve
The threads seem good on both the original and the replacement fittings -I can start them by hand and they work smoothly for two or three turns until I need use a wrench.
Darryl Meyers
1978 Eleganza II
El Dorado Hills, CA
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| Re: [GMCnet] Leaky brake fitting [message #226339 is a reply to message #226334] |
Sun, 20 October 2013 22:01 |
Darryl
Messages: 144
Registered: December 2011
Location: Northern California
Karma: 0
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Senior Member |
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Jim
I got a new brass valve from JimK in May. Since I've tried two separate fittings into the valve I think your analysis may be correct. I plan to call Nick first thing in the morning to make sure he has one in stock and may make the five hour round-trip to pick up a replacement. That should put the coach in the driveway Tuesday morning, ready to load and we could leave first thing Wednesday morning. Alternative would be to have him ship one next day to arrive sometime Tuesday but that would probably cost me a day.
Normally, on a three-week trip I try not too be tied to a strict schedule but Susan has plans to tutor on the Navaho reservation next week (starting Sunday) and there are a couple of national parks I'd like to see on the way.
Darryl Meyers
1978 Eleganza II
El Dorado Hills, CA
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| Re: [GMCnet] Leaky brake fitting [message #226343 is a reply to message #226339] |
Sun, 20 October 2013 22:37 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Darryl,
Have you removed the combination valve and carefully examined the
troublesome seat with a magnifying glass? As much trouble as you've had, I
have to suspect a bad seat, which should be visible. If the seat's not
bad, then replacing the valve's not going to help and you'll be that much
farther behind.
If the seat's not perfect, then it may be feasible to use a flare saver.
If they're not available to meet your schedule, this may help:
http://www.gmcmhphotos.com/photos/g4452-flare-fitting-repair-with-copper-seal.html
You may also want to check whether the seat is integral to the valve --
they're sometimes replaceable and you may find replacement seats available
locally.
HTH,
Ken H.
On Sun, Oct 20, 2013 at 11:01 PM, Darryl Meyers <hospacctg@att.net> wrote:
>
>
> Jim
>
> I got a new brass valve from JimK in May. Since I've tried two separate
> fittings into the valve I think your analysis may be correct. I plan to
> call Nick first thing in the morning to make sure he has one in stock and
> may make the five hour round-trip to pick up a replacement. That should
> put the coach in the driveway Tuesday morning, ready to load and we could
> leave first thing Wednesday morning. Alternative would be to have him ship
> one next day to arrive sometime Tuesday but that would probably cost me a
> day.
>
> Normally, on a three-week trip I try not too be tied to a strict schedule
> but Susan has plans to tutor on the Navaho reservation next week (starting
> Sunday) and there are a couple of national parks I'd like to see on the way.
>
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Leaky brake fitting [message #226349 is a reply to message #226343] |
Sun, 20 October 2013 23:19 |
Darryl
Messages: 144
Registered: December 2011
Location: Northern California
Karma: 0
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Senior Member |
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Thanks, Ken
I was so frustrated when I gave up this afternoon that I didn't pull the valve. The coach is 20 miles up the hill so my plan at this point is to go down to Fremont and pick up a new valve tomorrow, stopping in West Sacramento to pick up a new line and fitting.
I'll take a close look at the old valve when I pull it off but after not being able to get a clean connection with two fittings I think the odds are that the valve is bad. When I get the new line and fittings I will ask if they have any "flare savers" or know where to find some.
Darryl Meyers
1978 Eleganza II
El Dorado Hills, CA
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| Re: [GMCnet] Leaky brake fitting [message #226366 is a reply to message #226349] |
Mon, 21 October 2013 08:08 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| Darryl wrote on Mon, 21 October 2013 00:19 |
Thanks, Ken
I was so frustrated when I gave up this afternoon that I didn't pull the valve. The coach is 20 miles up the hill so my plan at this point is to go down to Fremont and pick up a new valve tomorrow, stopping in West Sacramento to pick up a new line and fitting.
I'll take a close look at the old valve when I pull it off but after not being able to get a clean connection with two fittings I think the odds are that the valve is bad. When I get the new line and fittings I will ask if they have any "flare savers" or know where to find some.
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Darryl,
If a good line has been put in a bad hole, it will now be bad also. I happen to love flare fittings, but I can tell you right here that if one is not right, there is little you can do to save it.
One test I always do when an inverted flare is having any kind of a problems is I run a flare nut into the hole. If it won't bottom out when tightened with fingers only, there is a problem in the threads.
The flare gaskets you thinking about are available at any refrigeration supply store.
Good Luck Guy,
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Leaky brake fitting [message #226498 is a reply to message #226370] |
Mon, 21 October 2013 22:40 |
Darryl
Messages: 144
Registered: December 2011
Location: Northern California
Karma: 0
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Senior Member |
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Rob
The "pigtail" sits on top of the combination valve and activates the brake warning light. There's probably a more descriptive name but that's how JimK referred to it on his website. It looks like you should be able to press it down and have it "latch" with the fitting on top of the valve but I tried everything (including a vice) and no matter how much pressure I applied it just wouldn't catch. The valve must be made in China and the "pigtail" in Taiwan or . . . But if you just seat it firmly on top of the valve it seems to work although if the red light doesn't come on when you turn the key you might need to go out and jiggle it a little to restore the connection.
Darryl Meyers
1978 Eleganza II
El Dorado Hills, CA
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| Re: [GMCnet] Leaky brake fitting [message #226504 is a reply to message #226498] |
Mon, 21 October 2013 23:11 |
Darryl
Messages: 144
Registered: December 2011
Location: Northern California
Karma: 0
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Senior Member |
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So, I called Nick first thing this morning to verify that he had a valve in stock and headed down to Fremont (actually, Newark). I stopped in West Sacramento to have a new brake line (with new fittings) made up ($23 plus change) and continued on down to Applied. Arrived about 11:00 - Nick had the valve waiting for me and also gave me a "flare saver" which he thought (and others have suggested) might solve the problem. Got home about 1:30 and headed up to Placerville and the coach.
I tried the "flare saver". As I was installing it my thought was, "hey, if this works it will be like magic" (at least, compared to the alternative). Well, it didn't work. I unscrewed the leaky fitting in the valve line, put the "flare saver" on top of the flare, pushed the line up into the connection and tightened the fitting. I fired up the engine and stepped on the brake and it slowly sank toward the floor. Did this 4-5 times and checked the level in the MC - down a half inch or so. Damn, that would have been so easy.
So, time for plan B. I pulled all the lines off the valve and removed the valve. It looked like the "flare saver" had seated properly and should not have leaked but. . .
I installed the new line to the new valve on the bench so I could make certain it was straight and as tight as possible and then installed the valve and connected the other lines. By this time it's about 5:00 and I don't have the brake fluid I need to pressure-bleed the brakes (thank you, Jim Hupy) so I pulled the rear wheels (For some reason, I find I need three hands to bleed the rear brakes without removing the wheels.) and attached the aluminum plate of the pressure bleeder to the MC and head home.
First thing in the morning I'll head up the hill, pick up a couple of quarts of brake fluid and bleed the brakes. At that point I will know if I have solved the problem. Everything went together smoothly so there is no reason why it shouldn't work properly but. . . Bleeding should take a half hour, then a couple of hours to remount the wheels and get the coach on the ground and then head down to load up for the trip.
We might get away tomorrow after all.
Darryl Meyers
1978 Eleganza II
El Dorado Hills, CA
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| Re: [GMCnet] Leaky brake fitting [message #226507 is a reply to message #226506] |
Mon, 21 October 2013 23:53 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Oops!
Forgot the link to the combination valve:
http://www.gmcmhphotos.com/photos/member-galleries/p37696-combination-valve-cros.html
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Rob Mueller
Sent: Monday, October 21, 2013 11:51 PM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Leaky brake fitting
Daryl,
Here is a link to a cross section of the combination valve with a description of how it works.
I think I understand what you're saying now. The electrical connector (pigtail) won't fit on the electrical plug on the combination
valve.
This:
http://www.appliedgmc.com/prod.itml/icOid/611
Won't fit properly on the white connector on the combination valve:
http://www.appliedgmc.com/prod.itml/icOid/770
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Darryl Meyers
Sent: Monday, October 21, 2013 10:41 PM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Leaky brake fitting
Rob
The "pigtail" sits on top of the combination valve and activates the brake warning light. There's probably a more descriptive name
but that's how JimK referred to it on his website. It looks like you should be able to press it down and have it "latch" with the
fitting on top of the valve but I tried everything (including a vice) and no matter how much pressure I applied it just wouldn't
catch. The valve must be made in China and the "pigtail" in Taiwan or . . . But if you just seat it firmly on top of the valve it
seems to work although if the red light doesn't come on when you turn the key you might need to go out and jiggle it a little to
restore the connection.
Darryl Meyers
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Leaky brake fitting [message #226517 is a reply to message #226507] |
Tue, 22 October 2013 00:35 |
jim kanomata
Messages: 257
Registered: March 2007
Location: fremont,ca
Karma: 12
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Senior Member |
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I do not have time to read all comments, so I suggest you call us and we will supply you with Copper flared washers to use.
It is a common practice to use them.
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Leaky brake fitting [message #226526 is a reply to message #226504] |
Tue, 22 October 2013 07:22 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Darryl,
It's probably so obvious that you didn't bother, but I don't see any
mention of the suspect fitting (only) being doused with all that brake
fluid from the MC.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL
www.gmcwipersetc.com
On Tue, Oct 22, 2013 at 12:11 AM, Darryl Meyers <hospacctg@att.net> wrote:
>
> ...I tried the "flare saver". As I was installing it my thought was,
> "hey, if this works it will be like magic" (at least, compared to the
> alternative). Well, it didn't work. I unscrewed the leaky fitting in the
> valve line, put the "flare saver" on top of the flare, pushed the line up
> into the connection and tightened the fitting. I fired up the engine and
> stepped on the brake and it slowly sank toward the floor. Did this 4-5
> times and checked the level in the MC - down a half inch or so. Damn, that
> would have been so easy.
...
>
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GMCnet mailing list
Unsubscribe or Change List Options:
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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