Home » Public Forums » GMCnet » Ken's hydroboost
| Ken's hydroboost [message #281997] |
Mon, 13 July 2015 10:29  |
Jim Wagner
Messages: 339
Registered: February 2004
Location: Brook Park, Oh
Karma: 0
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Ken
Have you done a write up on your hydroboost conversion. With photos I hope. I installed a hydroboost unit on Sandy's Corvette and was amazed in the braking.
Jim Wagner
Brook Park, oh
76 GMC500
71 Vega355
69Vette 383
There are so MANY possibilities that I don't know where to start (and I'm
in the midst of a Hydroboost installation on my 1-Ton+Manny Brakes equipped
23', which has had just about every brake combination you can think of.
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| Re: [GMCnet] Ken's hydroboost [message #282011 is a reply to message #281997] |
Mon, 13 July 2015 15:27  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Jim,
No, I haven't written, nor prepared any photos or notes on my
installation. It's sort of an experiment between Bob Stone and me. I
insisted, because of the constraints imposed by my custom dash, on using
the OEM pedal brackets. There was no obvious way around modifying the
pedal, shaft, and bellcrank, so Bob came up with one I have installed. It
was necessary to shim the top of the hydroboost to achieve the necessary
input rod angle, but I think that's probably a good thing, as far as hood
clearance.
I'm still using the 1-1/4" MC until I figure out what's going on with
pressures with that combined with 6 wheel discs. Some of us did tests at
Bean Station and concluded that the normal connections do not provide
enough fluid capacity for the 4 rear calipers -- we couldn't achieve as
much line pressure in the rear system as in the front. I've pretty much
confirmed that with the Hydroboost installed -- 600 psi front, 400 psi
rear. Yesterday, I reversed the line connections at the MC and now get 850
psi front and rear (read from the two 2000 psi gauges I have installed just
below the loops at the MC).
That's still not as much pressure as I want and expect from the Hydroboost,
but my braking is much improved from what its always been. I suspect part
of the problem is a little more residual air in the brake lines. More, I
don't think my PS output pressure is as high as it should be. I've never
had as light steering as most GMC's I've driven, and now, with the
Hydroboost and pressure lines near the firewall, I hear (and can feel on
the lines) a lot of pulsations. I'm considering whether to connect a
pressure gauge or just replace the pump. With 95+ temperatures &
humidities here now, there's not much chance I'll do anything soon. :-)
If I ever get done tinkering, I might write something up (after all, I've
only been tinkering with GMC brakes for 15 years now!).
Oh yeah, where can I find your writeup on the Corvette installation? :-))
Ken H.
On Mon, Jul 13, 2015 at 11:29 AM, Jim Wagner wrote:
> Ken
> Have you done a write up on your hydroboost conversion. With photos I
> hope. I installed a hydroboost unit on Sandy's Corvette and was amazed in
> the
> braking.
> Jim Wagner
> Brook Park, oh
> 76 GMC500
> 71 Vega355
> 69Vette 383
>
>
> There are so MANY possibilities that I don't know where to start (and I'm
> in the midst of a Hydroboost installation on my 1-Ton+Manny Brakes
> equipped
> 23', which has had just about every brake combination you can think of.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Ken's hydroboost [message #282019 is a reply to message #282013] |
Mon, 13 July 2015 16:44 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Johnny,
1. The Hydroboost is equipped with a small accumulator, spring loaded on
some, nitrogen filled on others. Nominally, after PS pressure failure it
should provide one stop at 1/2 boost, another at 1/4 boost. Mine won't
meet even the first, much less the second. I suspect most are that way.
I've heard that the handicapped van industry uses an electric backup pump.
I haven't really investigated that possibility yet. There is another
variant, the HydroMax, with uses an internal electric pump rather than PS
pressure. Others are investigating that, but it may be overkill; the
smallest bore available in its unique MC is, IIRC, 1-3/4". If it can put
out 1200+ psi with that volume, it would be greeeat -- but I know nothing
about its space requirements.
Another problem with the tiny accumulator, in my case, is that I've for
years depended on a pneumatic cylinder beneath the floorboard to pull the
brake pedal down for my "parking brake". Its tiny compressor, and the
electric vacuum boost pump, would work for as long as the battery held out
-- probably days to weeks, considering how seldom they ran. That's now
good only if the motor's running. :>(
2. The electric wipers should not interfere with the Hydroboost nor vice
versa -- the Hydroboost is plumbed between the pump and the steering box,
and has a separate return to the PS reservoir. So, if the pump provides
enough pressure for brakes and steering, there should be no problem with
the wipers.
Now why didn't I say, "YES, everyone needs my electric wiper kit!"???
Dumb! :-)
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, etc., etc.
www.gmcwipersetc.com
On Mon, Jul 13, 2015 at 4:39 PM, Johnny Bridges wrote:
> Ken -
>
> A couple of questions...
> 1. Is there a provision for some sort of residual reservoir to keep a bit
> of pressure up in an engine out situation?
> 2. Is this going to require an electric wiper retrofit? i.e. are stock
> wipers gonna affect braking pressure when they're running?
>
> Poorly informed minds want to know :)
>
> --johnny
>
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Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Ken's hydroboost [message #282023 is a reply to message #282011] |
Mon, 13 July 2015 16:50 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Ken, if you are fighting a hood clearance issue, Dodge full size vans used
a right angle bracket that had a belcrank. The bracket bolted to the
firewall, and the MC bolted to the bracket at a right angle. Would provide
plenty of space for the booster and hydro boost stuff and still close the
hatch. These were used in 3/4 and 1 ton box vans as well as van chassis
motor homes. Should be a bunch of them in salvage yards. Jus a thought.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Jul 13, 2015 1:28 PM, "Ken Henderson" wrote:
> Jim,
>
> No, I haven't written, nor prepared any photos or notes on my
> installation. It's sort of an experiment between Bob Stone and me. I
> insisted, because of the constraints imposed by my custom dash, on using
> the OEM pedal brackets. There was no obvious way around modifying the
> pedal, shaft, and bellcrank, so Bob came up with one I have installed. It
> was necessary to shim the top of the hydroboost to achieve the necessary
> input rod angle, but I think that's probably a good thing, as far as hood
> clearance.
>
> I'm still using the 1-1/4" MC until I figure out what's going on with
> pressures with that combined with 6 wheel discs. Some of us did tests at
> Bean Station and concluded that the normal connections do not provide
> enough fluid capacity for the 4 rear calipers -- we couldn't achieve as
> much line pressure in the rear system as in the front. I've pretty much
> confirmed that with the Hydroboost installed -- 600 psi front, 400 psi
> rear. Yesterday, I reversed the line connections at the MC and now get 850
> psi front and rear (read from the two 2000 psi gauges I have installed just
> below the loops at the MC).
>
> That's still not as much pressure as I want and expect from the Hydroboost,
> but my braking is much improved from what its always been. I suspect part
> of the problem is a little more residual air in the brake lines. More, I
> don't think my PS output pressure is as high as it should be. I've never
> had as light steering as most GMC's I've driven, and now, with the
> Hydroboost and pressure lines near the firewall, I hear (and can feel on
> the lines) a lot of pulsations. I'm considering whether to connect a
> pressure gauge or just replace the pump. With 95+ temperatures &
> humidities here now, there's not much chance I'll do anything soon. :-)
>
> If I ever get done tinkering, I might write something up (after all, I've
> only been tinkering with GMC brakes for 15 years now!).
>
> Oh yeah, where can I find your writeup on the Corvette installation?
> :-))
>
> Ken H.
>
>
>
> On Mon, Jul 13, 2015 at 11:29 AM, Jim Wagner wrote:
>
>> Ken
>> Have you done a write up on your hydroboost conversion. With photos I
>> hope. I installed a hydroboost unit on Sandy's Corvette and was amazed in
>> the
>> braking.
>> Jim Wagner
>> Brook Park, oh
>> 76 GMC500
>> 71 Vega355
>> 69Vette 383
>>
>>
>> There are so MANY possibilities that I don't know where to start (and I'm
>> in the midst of a Hydroboost installation on my 1-Ton+Manny Brakes
>> equipped
>> 23', which has had just about every brake combination you can think of.
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
> _______________________________________________
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| Re: [GMCnet] Ken's hydroboost [message #282029 is a reply to message #282023] |
Mon, 13 July 2015 17:31 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Thanks, Jim, I haven't yet tried a P30 MC, which may create a clearance
problem. If it does, and yet proves desirable with the HB, I'll check out
those vans. If the wiper and mount doesn't interfere, that would seem to
be a good way to perhaps eliminate the need for ANY changes to the OEM
pedal assembly. Since the big problem for HB installation is its excessive
extension through the firewall, rotating the assembly might make the task
easier.
Ken H.
On Mon, Jul 13, 2015 at 5:50 PM, James Hupy wrote:
> Ken, if you are fighting a hood clearance issue, Dodge full size vans used
> a right angle bracket that had a belcrank. The bracket bolted to the
> firewall, and the MC bolted to the bracket at a right angle. Would provide
> plenty of space for the booster and hydro boost stuff and still close the
> hatch. These were used in 3/4 and 1 ton box vans as well as van chassis
> motor homes. Should be a bunch of them in salvage yards. Jus a thought.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403
>
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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] Ken's hydroboost [message #282031 is a reply to message #282023] |
Mon, 13 July 2015 18:00 |
Hal StClair
Messages: 971
Registered: March 2013
Location: Rio Rancho NM
Karma: -12
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Ken, just question on your Hydroboost. What unit did you use and how did you deal with the HB's longish arm or were you able to source a short one?
Thanks, Hal
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."
1977 Royale 101348,
1977 Royale 101586, Diesel powered,
1974 Eagle Bus 45',w/slideout,
Rio Rancho, NM
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| Re: [GMCnet] Ken's hydroboost [message #282037 is a reply to message #282031] |
Mon, 13 July 2015 18:35 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Hal,
I don't know the ID of the HB I got from Bob Stone (dealing exclusively
through JimK). He had it rebuilt, with specific internals from perhaps
"any" HB. The input shaft is probably the only truly unique part of it
however: it's custom made for Bob to allow us to use the HB with our
close-coupled pedal assembly.
I have a couple of other HB's, probably from AstroVans, on the work bench.
Other than that input shaft, they all look identical.
Ken H.
On Mon, Jul 13, 2015 at 7:00 PM, Hal StClair
wrote:
> Ken, just question on your Hydroboost. What unit did you use and how did
> you deal with the HB's longish arm or were you able to source a short one?
> Thanks, Hal
> --
>
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Ken's hydroboost [message #282048 is a reply to message #281997] |
Mon, 13 July 2015 20:13 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Many step vans (called 'bread trucks' around here) also use the right angle bracket and bellcrank. We had a couple of promotional vehicles set up that way. I don't think there's room in a GMC for one. And the question was about stock wipers, which is what I think you meant in your answer though you said 'electric'.
I look forward to the results.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: Ken's hydroboost [message #295363 is a reply to message #282048] |
Wed, 10 February 2016 23:06 |
Hal StClair
Messages: 971
Registered: March 2013
Location: Rio Rancho NM
Karma: -12
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Senior Member |
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Bringing up an old post but was wondering if you were able to get the pressures up on your hydro boost system Ken? Did you change to the 34mm master cylinder and if you did, did you keep the front and rear brake lines reversed? I've got to address mine shortly and was just wondering how you made out. Thanks, Hal
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."
1977 Royale 101348,
1977 Royale 101586, Diesel powered,
1974 Eagle Bus 45',w/slideout,
Rio Rancho, NM
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| Re: [GMCnet] Ken's hydroboost [message #295364 is a reply to message #295363] |
Wed, 10 February 2016 23:41 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Bob has put in considerable time and resources to get it to this stage, so
were sort of protecting most of the set up.
He has been on the for few years and have discussed with Bob Drews and few
other people at the factory that manufacture components.
I know Wally Anderson has one of our kit on.
On Wed, Feb 10, 2016 at 9:06 PM, Hal StClair
wrote:
> Bringing up an old post but was wondering if you were able to get the
> pressures up on your hydro boost system Ken? Did you change to the 34mm
> master
> cylinder and if you did, did you keep the front and rear brake lines
> reversed? I've got to address mine shortly and was just wondering how you
> made
> out. Thanks, Hal
> --
> 1977 Royale 101348,
>
> 1977 Royale 101586,
>
> 1974 Eagle Bus 45',w/slideout
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Ken's hydroboost [message #295375 is a reply to message #295363] |
Thu, 11 February 2016 08:06 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Hal,
Bob Stone sent me a replacement Hydroboost which alone increased my lbrake
pressure from the 800 psi range to 1200 psi. That's with the 1-1/4" MC,
which I'm still using. According to Bob, teardown of the old Hydroboost
revealed an orifice (which one we don't know) that was undersized vs the
current one. I still have the excessive noise from the hoses, but Bob
reports progress at reducing that -- seems some hoses suppress noise better
than others. Also, I'm still running an OLD PS pump which I fitted with
what should have been a high pressure output regulator; a rebuilt pump may
be in order.
I'm still not getting the 1800 psi brake line pressure reported by some,
but the fact is, I can "stand the coach on end" with what I've got. My EBC
yellow brake pad tests some years ago yielded 55 mph to 0 mph stops on the
order of 255'. I haven't set up the test rig and duplicated those tests,
but it seems to me I'm now getting more on the order of 175' stops!
Until the weather warms up, I get SS brake lines, and the PS hose noise
problem seems resolved, I'm happy with what I've got.
HTH,
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, etc., etc.
www.gmcwipersetc.com
On Thu, Feb 11, 2016 at 12:06 AM, Hal StClair
wrote:
> Bringing up an old post but was wondering if you were able to get the
> pressures up on your hydro boost system Ken? Did you change to the 34mm
> master
> cylinder and if you did, did you keep the front and rear brake lines
> reversed? I've got to address mine shortly and was just wondering how you
> made
> out. Thanks, Hal
> --
>
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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: Ken's hydroboost [message #295383 is a reply to message #295378] |
Thu, 11 February 2016 12:22 |
Adrien G.
Messages: 474
Registered: May 2008
Location: Burns Flat, OK 73624
Karma: 1
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Senior Member |
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On vac boost system we've added a reserve vac tank and aux vac pump for braking applications if the engine should stop
at inopportune time.
What reserve braking capability after engine stop does the hydroboost system have?
My 1980 Olds diesel with hydroboost had good brakes, but when engine stopped, only one reserve brake application.
Good brakes is nice to have, but brakes that can stop on a dime with a nickle change (dislodging items, cabinets or ?)can be hazardous for passengers.
Just wondering, and curious mind.
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: [GMCnet] Ken's hydroboost [message #295385 is a reply to message #295383] |
Thu, 11 February 2016 13:17 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Adrien,
Reserve braking is one place the Hydroboost is REALLY lacking: If the PS
pump fails/quits with the engine, there's nominally one application left --
AT 1/2 NORMAL braking force. Maybe 25% for a second one, then leg power
alone. Remember I said my EBC yellow pad tests showed 255' to stop from 55
mph with vacuum and 140 lbf on the pedal? With no vacuum, that same
scenario gave 625' to stop. Just a little too long for comfort. Even
having just a 4"x30" vacuum reserve tank will give about 4-5 near-full
force stops with the vacuum booster.
Stopping with change isn't my objective. Maximum possible braking IS. In
my mind, the only way to be sure of being able to achieve that is by having
the capability to lock up all 6 wheels (10 if towing), at the same time.
Dream on, Old Man. :-)
Ken H.
On Thu, Feb 11, 2016 at 1:22 PM, Adrien Genesoto wrote:
> On vac boost system we've added a reserve vac tank and aux vac pump for
> braking applications if the engine should stop
> at inopportune time.
> What reserve braking capability after engine stop does the hydroboost
> system have?
> My 1980 Olds diesel with hydroboost had good brakes, but when engine
> stopped, only one reserve brake application.
>
> Good brakes is nice to have, but brakes that can stop on a dime with a
> nickle change (dislodging items, cabinets or ?)can be hazardous for
> passengers.
>
> Just wondering, and curious mind.
>
>
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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] Ken's hydroboost [message #295391 is a reply to message #295390] |
Thu, 11 February 2016 16:41 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Larry,
I've heard that their are electric backup pumps for PS & Hydroboost used in
handicapped vans. I suspect they're used in similar applications as you
suggest. I haven't yet investigated.
Incidentally, before the recent change-over, I had basically the same
configuration you describe except that I have the PVC tube reservoir in
addition to the Azure pump, and had a vacuum gauge dedicated to that
system. I never had any shortage of vacuum, but this new setup feels as if
I've got 50% more braking power per lbf on the pedal.
Ken H.
On Thu, Feb 11, 2016 at 5:03 PM, Larry wrote:
> I have a Dave L vacuum booster with the Azure vacuum pump for backup.
> Just so I know where I stand with this setup, on a back deserted back road,
> I
> turned on the vacuum pump and shut the engine off at 55 mph. The pump
> easily kept up with vacuum needed (even with pumping the brakes) to bring
> the
> coach to a normal stop. I do not have a vacuum can for storage. Yet the
> pump kept up with plenty of vacuum for stopping.
>
> It would seem like there must be some kind of power back-up for the
> hydro-boost. Seems like it would be required on people movers, school
> busses and
> the like?
> --
>
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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