Hydro Boost Brakes

[zebrabeefj40]

Add to your list of donor vehicles mid 80's full size GM cars (had a '85 Chevy wagon w/305 V8 and hydroboost) and early '90's 3500 series heavy duty vans (have a '93 GMC 3500HD Vandura w/a 5.7L V8 and hydroboost. It is also found on some GMC Topkick truck chassis with an electric backup pump. IE if motor stalls a sensor notices the loss of boost pressure and will kick in an electric pump to maintain boost pressure to the brake system so you can still stop. My uncle's '90 GMC Topkick rollback has this system; works well for stopping a 26K truck...

HTH,
Nick

 

[Tapage]

Hey .. back in the thread .. Peter did you have pics of this system and modd that you meka to your rig . ? hey I need brakes here we have many of astro van, but all are Gas engine not diese . ? dosen't matter . ?

I want to be clear about the master cilinder .. where 2 upgrades involved, no alternator with vacumm pump and well better brakes. But is a issue change your PS pump . ? I have my Toyota poor PS pump ..

 

[Fromage]

Caution, when the engine stops, however, you don't get a pump or two of the pedal before you run out of vaccuum, when the engine stops, you got no power assist. Like other brakes, however, you can still stop by pressing real hard.

Peter Straub

That's not entirely correct. Most pass car and light truck hydroboost have a gold canister on the side, it's a hydraulic accumulator. Perhaps TippyR's is siezed? I get three full pumps on Brutus (Land-Rover 5.9CTD on 4wheel range rover discs, custom Eaton axles and 325/85R16s XMLs, hydroboost from 87 3/4 ton Chev diesel and locks em up.)

 

[Fromage]

btw, my eyes were opened back a few years when i was involed in an accident in a winter snow storm. i slid down a long icy hill and "T"boned a car pushing her into a van. the final bill 2 years later was $250,000. i darn near had a heart attack until the insurance company said they are comvering the bill. the problem was i had a 1000 lb work box in the back of my pickup and i had not notified my insurance. at first they were not going to cover me but in the end they did. right after that they dropped coverage on me. i asked why and the answer was since the box did not cause the accident i would be covered but since i did not notify them of the box i became a high risk. if they had felt the box had in any way contributed to the accident then my coverage would have been nulified...

Anyone here from Ontario?

I've had nothing but headaches with insurance for modified vehicles. No one will insure them here. Luckily my BJ60 is all stock, but the Land-Rover isn't and I'm really worried about this kind of stuff. Anyone in Ontario have had luck with declaring your mods and not being dropped point-blank?

 

[lshobie]

JL, call me. I have a guy who can probably do it for you. He probably won't if your driving record is bad though.

REgards

 

[tlcruiserman]

I thought about this for a while and I think it would work great for some applications and is very cool. I would not want to run application on one of my trucks I wheel a lot. I really do not want to have to choose between brakes and steering, sometimes I need both and a lot of them. but of other applications would probably be fine. I thought about upgrading the braking system to what my 100 has, but considering the costs that land pimp points out I think I will stick with what I have for now.

Cheers,

Michael

 

[Behemoth60]

Most pass car and light truck hydroboost have a gold canister on the side, it's a hydraulic accumulator. Perhaps TippyR's is siezed?

Interesting. I've always wondered what that canister was for. TippyR definately has it, but it definately doesn't do anything. The brakes are very much compromised the instant the engine is off.

And to TLCCRUISERMAN.... I don't think you have to 'choose' between steering and brakes with a hydro system.. If you loose hydro pressure to a stock steering system, your steering may be a bit tougher, but by no means missing! TippyR actually IS fully hydro steer, but I've addressed this with seperate priority valves for brakes and steeringoff the main pressure line, although I did put the brake priority valve before the steering one. If I ever do have to make a choice, it will be Brakes on a rig like Tippy.

Tapage and Radd Cruisers... No need to upgrade your stock pumps. This system was designed for use with a single stock P/S pump. Definately of most value for bigger tires, but also of particular interest to those that may tow larger trailers.

And to all you Insurance thread hi-jackers... I carefully avoided hi-jacking another thread by starting this one. Get the f**$ off my thread.

Peter Straub

 

[crustyBJ60]

interesting this....

when you "made" new lines, custom? what was the cost?

i'd like to see how you did the adapter plate.. pics?

i had some discussion with a mechanic (i work with several) today about the hydroboost idea.

the only thing i was warned about was the possible scoring on the shaft in a high milage system, you can replace the seals, but not really "rebuildable" was the general thought.

anyone have any idea what a new set-up might cost? not "cheap" i'm sure, but if it's less than the toyota gear...

i too would like to be rid of that horrid little alt. and vac. set up. it works ok when it works, but $$$ to replace and i have had to do it a couple of times (and will again i'm sure). then i can go to an alt. with some REAL amps.

then maybe i can stop buying parts trucks for just the starters and alts.

now i can just get them for other reasons

crusty

 

[dieselcruiserhead]

The hydroboost has three ports, one from the PS pump, one that leaves the booster that goes to the PS box (still high pressure) and a low pressure return that goes back to the PS pump or reservior. At first I had just my PS hooked up and it *actually got better* and smoother with the hydroboost added. But my pump was designed for hydroboost and is a saginaw. I would be worried about possibly using it with a Toyota pump but at the same time I don't think it actually takes much energy at all but I may be wrong. I say try it out and if it fails then switch to a saginaw pump...

 

[Radd Cruisers]

The hydroboost has three ports, one from the PS pump, one that leaves the booster that goes to the PS box (still high pressure) and a low pressure return that goes back to the PS pump or reservior. At first I had just my PS hooked up and it *actually got better* and smoother with the hydroboost added. But my pump was designed for hydroboost and is a saginaw. I would be worried about possibly using it with a Toyota pump but at the same time I don't think it actually takes much energy at all but I may be wrong. I say try it out and if it fails then switch to a saginaw pump...

Its volume that I would be concerned with, but it sounds like Peter is using the toyota pump to power the system?


Crusty, I know that Commox auto recyclers had a bunch of ambulances with vacume electric vacume pumps for cheap.


Rob

 

[lowenbrau]

Peter most definitely is not using the Toyota pump. He has a huge, full time hydraulic pump on his to run his full hydro steering and hydro winch.

The "Toyota is inferior to Saginaw" monster is rearing its head again. Somebody point us to the link that shows the pressure and flow rates for both again.

 

[dieselcruiserhead]

FWIW I tried using regular brakes with an electric vaccuum pump on the 55 before I went to hydrobosot. The pump was a Thomas brand, very high quality (about the quality of an ARB compressor) and was $180 new - but my brakes still sucked... FWIW.. Andre

 

[Tapage]

Tapage and Radd Cruisers... No need to upgrade your stock pumps. This system was designed for use with a single stock P/S pump. Definately of most value for bigger tires, but also of particular interest to those that may tow larger trailers.

Peter, thanks for your time and lessons, did you still using with this system, stock Brake lines ( hard and flexible ) , stock cilinders ( rear ), calipers, pads .. etc . ?

 

[Overlord]

The only real mod is using a different brake master cyl instead of your stock one - if you choose to. The big difference is the BOOSTER hence why it is called hydroboost. You can leave as stock but the irony is it will stop much better with it than any stock setup with larger tires. It scares me to think what it would be like with normal tires. Probably complete utter overkill. An interesting thing is my power steering works much better with it as well. Before there were some flat spots at lower RPMs strangely enough...

So, you can still use your stock cruiser MC?

 

[Behemoth60]

Some answers...

Like Bruce said, Peter is not using stock ANYTHING on his brakes. Remember, this thing has unimog axles with custom disk brakes. Technically, the callipres are stock to the vehcile, but there's 8 of them on this rig instead of 2. But that's just what I did, for reasons other than because of the hydroboost.

The pump I uses is indeed a true and proper hydraulic pump, but like Bruce said, it's sized for winching, and full hydro steering and as an afterthought, used for brakes too. Again, although i haven't, I wouldn't hesitate to use a stock Toy pump.

I wouldn't bother trying to adapt the stock Master Cylendar to the hydro booster. The one that's attached to the booster will be at least as large, and make more than enough volume. You'll have to change the brake lines to whatever non-metric size you have for the master, but that's not overly challenging.

As for cost of new lines, etc.... In the interest of staying up-beat and positive about the whole TippyR project, I make a specific point of not keeping track of 'incidental' costs on TippyR and instead I like to rant about my unexplainably low bank balance.

As for pics, well, why don't you come wheeling with TippyR one day. I'll be happy to pop the hood and watch you struggle to get your head over the fender to look inside.

Peter Straub

 

[Fromage]

Here are my findings (which I believe relate more closely to stockish rigs than TippyR).

The pumps I have been using throughout the various incarnations of my Land-Rover has been a stock displacement automotive pumps sourced from various manufacturers. The Ford, Chevy and Dodge (Cummins?) pumps I have used have all been able to turn 900R16 michelins on dry pavement with no problem at all, whilst holding the vehicle on any grade. I have never had to use a high volume pump. The difference between brakes and steering is that the brake master requires very little flow but lots of pressure, and the box will work quite happily with lots of flow (albeit at a slightly lower pressure). Herculean pedal depression whilst whipping the steering from lock to lock will often result in a lumpy feeling as the pressure drops in the box, but the assist is still very much there. It is definitely not a "pick brakes or steering" affair.

You could probably use the stock master, but at a whole 27$, the C30 Chevy master, with 1 5/16 bore delivers lots of juice. Mine runs 4X 4 piston calipers and goes from full off to full lock in about 3" of pedal travel. I like it just like that, feels great.

Peter, I do apologize for my attempted hijack of your thread. You may be interested to know that the canister is removable and the accumulator rebuildable IIRC. They are known to sieze and I would imagine comprised within is some sort of a check valve to hold pressure at engine shutoff, which may be defective in your case.

 

[Fromage]

At first I had just my PS hooked up and it *actually got better* and smoother with the hydroboost added.

Gimme an A C C U M U L A T O R

Go Hydroboost !

 

[dieselcruiserhead]

The hydrobooster will put out a GM pattern. I believe one of the off road manufacturers sells a GM booster to Toyota adapter for the mini truck market that should work but I use the GM master and it is very powerful and works great. You just need to adapt the size of the brake lines (larger with the hydroboost) to TLC 1/8" with fittings and it works fine..

 

[Mark W]

Dredging up an old thread here... I noticed that in the discussion of accumulators and lack of power without the engine running, no one mentioned another option.

I drove an international bus for a while which had hydro boost brakes. If you stepped on the brakes without the engine running you'd hear an electric pump fire up. That was the backup. Full ( and sustained) braking power even with the engine turned off. Much better than an accumulator in my opinion.

Mark...

 

[FL cruiser]

I've made my own hydroboost adapter. Took an old mini truck booster, cut the mounting area with studs off the back with a die grinder. Then welded on a round washer in the center with the same inside ID as the hydroboost onto the plate I cut off the booster. Bolts right up to the LC firewall without having to do any firewall mods.
You can use the LC booster for a donor, if you don't mind destroying it, but minitruck boosters have the same mounting and pattern too.