Hydroboost differences.....

mrvette

mrvette

Phantom of the Opera
Joined
Mar 24, 2008
Messages
15,207
Location
NE Florida
Does anyone know if there are any internal/pressure/design differences in the various HB units out there???

I notice that the HB on the motor home leaves me with a very hard pedal, lots of pressure to stop the thing.....

but the one on the vette is marginally too much assist....but I"m used to it....

tempted to swap HB units just to see, but what say you all....???
 
No hardcore facts, just gut feeling. Different vehicle weight probably uses a different valve setup in the HB. I looked at one that was on a P-30 chassis and it was huge compared to the one on a car.
The one on your vette is touchy, can you dial back the pressure it sees? Have to use a restrictor/bypass setup or it'll overheat the fluid.
 
TimAT said:
No hardcore facts, just gut feeling. Different vehicle weight probably uses a different valve setup in the HB. I looked at one that was on a P-30 chassis and it was huge compared to the one on a car.
The one on your vette is touchy, can you dial back the pressure it sees? Have to use a restrictor/bypass setup or it'll overheat the fluid.
Click to expand...

The two units I have are identical exterior appearance, but I have never had the one on the vette, apart, I did have to take the camper unit apart as some lever got backhanded, ....

but you say the ones on a P30 frame are physically larger??

the vette has a serp drive, and a '72 valve in the PS pump, running a rack too you know, whole thing drives well, I think....

but it's a bit much to expect 130 lbs of Linda to stop the MH.....

:crutches::crap:
 
The HydroBeast was standard on a lot of GM trucks/vans and also a Cadillac. From what I've read, in a GM application the HB was very comparable to a power brake system using vacuum. When installed in a Corvette as an aftermarket installation, it seems the HB is very touchy and subject to immediate lockup.

Reading on the forums, leads me to think the HB is very sensitive to backpressure; i.e the fluid return line back to the PS pump cannot experience any backpressure at all. For original GM applications of the HB, a standard PS Saginaw PS pump was used....except it did have a special back shell on the pump housing to return fluid back into the pump reservoir. (The reservoir was also known as the ham can since it looked like a little Danish ham can.) Jim O'Shea, the Saginaw guru for PS for the C3's, said that the low pressure return line into the ham can for HB equipped GM vehicles was specifically designed to allow fluid to return with no back pressure. I bought one of these reservoirs (ham can) for my 70.
 
68/70Vette said:
The HydroBeast was standard on a lot of GM trucks/vans and also a Cadillac. From what I've read, in a GM application the HB was very comparable to a power brake system using vacuum. When installed in a Corvette as an aftermarket installation, it seems the HB is very touchy and subject to immediate lockup.

Reading on the forums, leads me to think the HB is very sensitive to backpressure; i.e the fluid return line back to the PS pump cannot experience any backpressure at all. For original GM applications of the HB, a standard PS Saginaw PS pump was used....except it did have a special back shell on the pump housing to return fluid back into the pump reservoir. (The reservoir was also known as the ham can since it looked like a little Danish ham can.) Jim O'Shea, the Saginaw guru for PS for the C3's, said that the low pressure return line into the ham can for HB equipped GM vehicles was specifically designed to allow fluid to return with no back pressure. I bought one of these reservoirs (ham can) for my 70.
Click to expand...

I have used a 3/8 T fitting for the return to the single input ham can on both installs, one of them the HB goes into the stem of the T, the other goes through the top of the T.....I forget which is which, and yes I have read the comments about the T fitting, but the vette is just right for pedal feel, far as I"m concerned....don't forget, I was desperate to get some solid pedal feel on the vette, fought it for years, finally gave up the ghost to a large truck master cyl....1 5/16? diameter piston....it was an improvement, but I still could push the pedal to the floor, so when doing the HB install, I never popped a brake line, when driving outta the driveway, going forward up hill, I tapped the brakes and tossed my nose into the steering wheel at full force....FINALLY had BRAKES!!!!, so I went back to an aluminum aftermarket stock size m/cyl....and it's been fine for years now, one other thing that did get done was to eliminate that brake pressure differential switch....

:thumbs:
 
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