| How hot should the rear wheels get? [message #217952] |
Mon, 12 August 2013 08:21  |
An87ttype
Messages: 157
Registered: September 2012
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I've finally gotten things together enough to take a couple of trips. One of the things that bothers me is how hot the rear wheels get. It seemed to start after replacing the master cylinder and brake lines. At first I thought the adjusters just adjusted the brakes up from finally having good brake pressure. I say that because at first only three of the wheels got hot. Now all four do. I've driven about 1000 miles since the brake work and they still get hot. The coach rolls easily and the parking brake works as it should. No bad sounds, just hotter than I would think.
Any thoughts?....thanks all
1975 Eleganza II
Hudson Valley NY
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| Re: How hot should the rear wheels get? [message #217956 is a reply to message #217952] |
Mon, 12 August 2013 08:37  |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Hard to guess, since " hot" is rather subjective measurement. One of the cheap HF infrared temp gauges can eliminate the guess of "hot.". If not dragging brake shoes, it may be wheel bearings. However, if they are roughly equal in heat level, it may be correct for your coach. Are they too hot to touch? Mine get warm, but I can touch them after a run done the road.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: How hot should the rear wheels get? [message #217962 is a reply to message #217952] |
Mon, 12 August 2013 08:55 |
An87ttype
Messages: 157
Registered: September 2012
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The drums are too hot to touch. Over 212F. A wet finger will sizzle on contact. This is after a 150 mile drive. The temp is about the same on all four. The wheels - Alcoa's - get hot but not too hot to touch. I think the bearings are ok for now. No bad sounds. It would also be a real coincidence that all four failed at the same time. I guess it could be normal. The coach does stop good so that's a plus.
1975 Eleganza II
Hudson Valley NY
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| Re: How hot should the rear wheels get? [message #217968 is a reply to message #217962] |
Mon, 12 August 2013 09:13 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
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Since you do not know what is causing your problem, I suggest the following.
Take the coach for a drive and after 10 or 15 minutes of not using the brakes, coast to a stop on the side of the road WITHOUT using the brakes. Now measure the temperature of the brake drums ans see what you have.
If they are too hot to touch then you do indeed have a problem.
It has to be either bearings too tight or brakes dragging.
Which one do you want to try first?
It would not take long to pop the wheel bearing caps and loosen each of the axle nuts one notch and go try driving it again.
The second item to try, is to go around and loosen up all 4 brakes on the rear wheels. Again I would go maybe 2 notches on each wheel. Then go drive it again checking for temperature built like you did at the beginning of this post.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: How hot should the rear wheels get? [message #217978 is a reply to message #217968] |
Mon, 12 August 2013 09:57 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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I'm guessing dragging brake shoes, since it is all four wheels. Perhaps during an application of the brakes, the rear shoes were engaged with the drums and did not release fully, continuing to drag on the drum. Check the parking brake setting, if it did not release, shoes will drag. I have driven several miles with the parking brake on. Dragging brakes should smell.
Try jacking up one side and spinning the rear wheels, while off the ground. Should feel the drag of the shoes or even hear it.
Then follow Ken B's advice.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
[Updated on: Mon, 12 August 2013 09:58] Report message to a moderator |
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| Re: How hot should the rear wheels get? [message #217995 is a reply to message #217952] |
Mon, 12 August 2013 11:54 |
Adrien G.
Messages: 474
Registered: May 2008
Location: Burns Flat, OK 73624
Karma: 1
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| An87ttype wrote on Mon, 12 August 2013 08:21 |
I've finally gotten things together enough to take a couple of trips. One of the things that bothers me is how hot the rear wheels get. It seemed to start after replacing the master cylinder and brake lines. At first I thought the adjusters just adjusted the brakes up from finally having good brake pressure. I say that because at first only three of the wheels got hot. Now all four do. I've driven about 1000 miles since the brake work and they still get hot. The coach rolls easily and the parking brake works as it should. No bad sounds, just hotter than I would think.
Any thoughts?....thanks all
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Besides what others have said, if the MC piston doesn't completely release the fluid port, then enough residual pressure is in the line to make the shoes drag to generate the heat and backing off the adjuster will not change anything.
MC push rod may be long, or ?.
FWIW my 2 cents.
Adrien & Jenny Genesoto
75 Glenbrook (26-3) Mods LS3.70 FD / Reaction Sys / 80mm Front&Intermidiate / Hydroboost / 16" Tires / Frame Rebuild / Interior Rebuild
Yuba City,Ca. Text 530-nine-3-three-3-nine-nine-6
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| Re: How hot should the rear wheels get? [message #217996 is a reply to message #217952] |
Mon, 12 August 2013 12:06 |
C Boyd
Messages: 2629
Registered: April 2006
Karma: 18
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Sir: using a laser temp my alum rear wheels shot between the lug bolts runs 108-109*. Fronts about 115*.
| An87ttype wrote on Mon, 12 August 2013 09:21 |
I've finally gotten things together enough to take a couple of trips. One of the things that bothers me is how hot the rear wheels get. It seemed to start after replacing the master cylinder and brake lines. At first I thought the adjusters just adjusted the brakes up from finally having good brake pressure. I say that because at first only three of the wheels got hot. Now all four do. I've driven about 1000 miles since the brake work and they still get hot. The coach rolls easily and the parking brake works as it should. No bad sounds, just hotter than I would think.
Any thoughts?....thanks all
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C. Boyd
76 Crestmont
East Tennessee
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| Re: How hot should the rear wheels get? [message #217997 is a reply to message #217995] |
Mon, 12 August 2013 12:08 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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| Adrien G. wrote on Mon, 12 August 2013 09:54 |
| An87ttype wrote on Mon, 12 August 2013 08:21 |
I've finally gotten things together enough to take a couple of trips. One of the things that bothers me is how hot the rear wheels get. It seemed to start after replacing the master cylinder and brake lines. At first I thought the adjusters just adjusted the brakes up from finally having good brake pressure. I say that because at first only three of the wheels got hot. Now all four do. I've driven about 1000 miles since the brake work and they still get hot. The coach rolls easily and the parking brake works as it should. No bad sounds, just hotter than I would think.
Any thoughts?....thanks all
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Besides what others have said, if the MC piston doesn't completely release the fluid port, then enough residual pressure is in the line to make the shoes drag to generate the heat and backing off the adjuster will not change anything.
MC push rod may be long, or ?.
FWIW my 2 cents.
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What Adrien said, above, is what I was thinking. Your statement " It seemed to start after replacing the master cylinder " is a dead giveaway.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: How hot should the rear wheels get? [message #218000 is a reply to message #217997] |
Mon, 12 August 2013 12:21 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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| Carl S. wrote on Mon, 12 August 2013 12:08 |
| Adrien G. wrote on Mon, 12 August 2013 09:54 |
| An87ttype wrote on Mon, 12 August 2013 08:21 |
I've finally gotten things together enough to take a couple of trips. One of the things that bothers me is how hot the rear wheels get. It seemed to start after replacing the master cylinder and brake lines. At first I thought the adjusters just adjusted the brakes up from finally having good brake pressure. I say that because at first only three of the wheels got hot. Now all four do. I've driven about 1000 miles since the brake work and they still get hot. The coach rolls easily and the parking brake works as it should. No bad sounds, just hotter than I would think.
Any thoughts?....thanks all
|
Besides what others have said, if the MC piston doesn't completely release the fluid port, then enough residual pressure is in the line to make the shoes drag to generate the heat and backing off the adjuster will not change anything.
MC push rod may be long, or ?.
FWIW my 2 cents.
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What Adrien said, above, is what I was thinking. Your statement " It seemed to start after replacing the master cylinder " is a dead giveaway.
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There was a thread here a while back about master cylinders and how they behave with disk brakes. The disk brake versions have a valve that keeps the fluid from all coming back when released. Drum brakes don't want that. So an OEM GMC MC has one valve in it for the disk brakes, and no valve in the drum brake section.
Or something like that.
Maybe he needs to swap the front/rear fittings.
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| Re: How hot should the rear wheels get? [message #218005 is a reply to message #217952] |
Mon, 12 August 2013 13:13 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| An87ttype wrote on Mon, 12 August 2013 09:21 |
I've finally gotten things together enough to take a couple of trips. One of the things that bothers me is how hot the rear wheels get. It seemed to start after replacing the master cylinder and brake lines. At first I thought the adjusters just adjusted the brakes up from finally having good brake pressure. I say that because at first only three of the wheels got hot. Now all four do. I've driven about 1000 miles since the brake work and they still get hot. The coach rolls easily and the parking brake works as it should. No bad sounds, just hotter than I would think.
Any thoughts?....thanks all
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Ann,
Get an infrared thermometer so you have some real data, but sizzle spit is too hot!
If that is real, you at least have a shoe dragging. If it is bearings, you have a real big problem.
Both before I got floating rear brakes made floating, what gets called reaction arms, I used to get front disks at about 190° and bearings at about 150° with intermediates at 150° on the drums and 90° on both front and rear bearings and 120° on the rear drums. Now, the bearings are still the same, but the disks are usually about 170° and the rear drums are all about 150°. Yes, it stops witht he rear brakes now.
You should be able to keep a finger on the drums. 150°F is about the limit of that.
Matt - on the way to Manitowoc
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: How hot should the rear wheels get? [message #218007 is a reply to message #218000] |
Mon, 12 August 2013 13:26 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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| Carl S. wrote on Mon, 12 August 2013 12:08 |
| Adrien G. wrote on Mon, 12 August 2013 09:54 |
| An87ttype wrote on Mon, 12 August 2013 08:21 |
I've finally gotten things together enough to take a couple of trips. One of the things that bothers me is how hot the rear wheels get. It seemed to start after replacing the master cylinder and brake lines. At first I thought the adjusters just adjusted the brakes up from finally having good brake pressure. I say that because at first only three of the wheels got hot. Now all four do. I've driven about 1000 miles since the brake work and they still get hot. The coach rolls easily and the parking brake works as it should. No bad sounds, just hotter than I would think.
Any thoughts?....thanks all
|
Besides what others have said, if the MC piston doesn't completely release the fluid port, then enough residual pressure is in the line to make the shoes drag to generate the heat and backing off the adjuster will not change anything.
MC push rod may be long, or ?.
FWIW my 2 cents.
|
What Adrien said, above, is what I was thinking. Your statement " It seemed to start after replacing the master cylinder " is a dead giveaway.
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"There was a thread here a while back about master cylinders and how they behave with disk brakes. The disk brake versions have a valve that keeps the fluid from all coming back when released. Drum brakes don't want that. So an OEM GMC MC has one valve in it for the disk brakes, and no valve in the drum brake section.
Or something like that.
Maybe he needs to swap the front/rear fittings."
I meant front/rear LINES at the master cylinder.
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| Re: How hot should the rear wheels get? [message #218084 is a reply to message #217952] |
Mon, 12 August 2013 22:42 |
An87ttype
Messages: 157
Registered: September 2012
Karma: 0
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Senior Member |
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Thanks all, as usual there is no shortage of information here!
I hope I can help clarify with a little more info as to what has been done. I'm sure it has to do with something I worked on.
The MC from Advanced Auto and a sensitized booster from JimB, SS lines front and back. POs shoes and discs looked like new. The coach stops straight, doesn't lock up prematurely. In my very slightly sloped dooryard, I can slowly release the parking brake and start rolling, pull up a little and stop.
After the brakes were bled, I did some back and forth braking to see how it felt, and to see if I could get a little more out of the adjusters. It did feel like I got a click out of a couple of them. The feel was great with the new booster and tight brakes. I drove it a few miles and felt the wheels to make sure nothing was stuck. I noticed that 3 wheels were a little warm and one was not. I figured it was just the shoes draging a bit from the adjusters doing their job. I patted myself on the back, and called it a job well done.
Now after about 1000 miles, I think maybe something is up. All four wheels definetally feel hotter than normal. Much hotter than the front. But there is no smell of excessive heat or burning. My spit finger says the drum was between 225 and 275 F? Of course only a guess, and it was after a 150 mile trip. Maybe it's normal?
It really is a great stopping coach. I don't want to fix it til it's broke if I don't have to. But since the brakes are a first priority, I'm wondering if I forgot or did something stupid. It wouldn't be the first time!
Thanks all!...
1975 Eleganza II
Hudson Valley NY
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| Re: How hot should the rear wheels get? [message #218134 is a reply to message #217952] |
Tue, 13 August 2013 10:25 |
An87ttype
Messages: 157
Registered: September 2012
Karma: 0
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Senior Member |
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I was just reading through this again and I'm wondering if the Advance Auto MC has some kind of check valve? Now I'm not really clear if I have the right MC. Did the Toro have a check valve? Is there any way to tell? It looks exactly the same as the old one. I'm also wondering if there should of been a spacer or somthing on the booster or MC that is missing. Wouldn't be the first time I lost something.
Thanks all...
1975 Eleganza II
Hudson Valley NY
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