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You mention the brake peddle is rock hard, is this with the car running and off or just with the car running?
If the lines to the R&P are crossed it will cause the pump to see max pressure and the peddle will be rock hard. There is a check valve in the outlet of the rack that will cause the blockage in the system if plumbed wrong.
Just throwing ideas out there to check,
Neal
Both running and stopped. The rack is brand new, so I'm going to check other possibilities first, like the HB not routing fluid to the steering because the bypass hole is blocked.
Don't think it's your issue but there are two different GM master cylinders and two different Hydroboost units, you cannot cross them or they will not work.
The pictures you posted of the HB unit are pics of a late model unit which will only work with a late model (shallow) master cylinder.
I found this info on the Hydratechbraking web site under the C3 units.
Don't think it's your issue but there are two different GM master cylinders and two different Hydroboost units, you cannot cross them or they will not work.
The pictures you posted of the HB unit are pics of a late model unit which will only work with a late model (shallow) master cylinder.
I found this info on the Hydratechbraking web site under the C3 units.
Neal
I didn't know that. I'll look into that and post what I find. Thank you Neal!
I spoke with Technical Support at both Hydratech (Jim, really nice guy, knows his stuff) and SpeedDirect (Chris, also a nice guy and knowledgeable).
Jim @ Hydratech said that, yes, I have a late (>1976) short actuator rod booster. If I had a mismatching master cylinder (early, deep), then I would have "no pedal" because the actuator rod wouldn't reach the MC piston without a "bullet" between the actuator rod and MC piston. I have the opposite problem - rock hard pedal pressure all the time but manual braking at best.
He also said the no steering assist doesn't make sense either because the HB is a complete pass through system when not braking. Jim thinks something is getting hung up somewhere and told me to check the pedal rod from the pedal through the firewall. It should level to 6 degrees.
Chris @ SD didn't have an answer for the no assist from a new R&P unit. He looked up the serial number of the R&P I ordered last September. It has passed the bench tests.
I made a diagram of the HB, PS pump and R&P steering fluid route.
PS pump to HB high pressure in, to HB pressure out to Steeroids high pressure in and HB low pressure to the return T fitting.
I added the Perma-Cool fluid cooler when I switched to a higher volume PS pump, so that is a suspect now. I also have one woven SS over TFE hose. As v2racing said, those can collapse and block flow. (I had another braided hose that failed a few years ago that I replaced with a conventional pressure hose.)
My next steps are to replace the braided line and test the cooler flow.
Does anybody have ANY other diagnostic ideas I can try?
her is your problem... the space between the steroids and the master cylinder is to close, if you have an wilwood M/C they gave you a small, about 1" long, i thick, rod extension, this is about 1/8 to 1/4" to long. take the pice out then drill the pocket in the back of the rod deeper.. problem resolved.
May be time to isolate each component in the system and remove one at a time from the equation.
Get a fitting that will allow you to bypass the HB unit, if that don't solve the power steering issue then re-connect the HB and bypass the R&P unit and see if the HB will work.
her is your problem... the space between the steroids and the master cylinder is to close, if you have an wilwood M/C they gave you a small, about 1" long, i thick, rod extension, this is about 1/8 to 1/4" to long. take the pice out then drill the pocket in the back of the rod deeper.. problem resolved.
I have Wilwood brakes but I don't have a Wilwood MC, and I didn't get a rod extension with the MC (a "bullet" as Jim @ Hydratech called it). However I am suspicious of the clearance between the actuator rod and the MC piston. I know there should be about 0.020" between them, and if there isn't any or isn't enough clearance, then I was planning to shorten the actuator rod instead of drilling out the MC.
Thanks for the suggestion. I'll post measurements and pics when I open things up again.
As I said, the brake pedal was rock hard all the time, engine running or stopped. I drained and removed the master cylinder last night and tried the brake pedal again. It went to the floor, so that means the pedal rod is not getting hung up through the firewall. The Hydroboost and MC are both the late (>1976) short/shallow type, so that wasn't causing the problem.
Then I tried pushing the MC piston into the MC. It couldn't budge it by hand. I put the MC piston end down on a ratchet extension to press harder. It took a lot of force to move it, and when it moved, it was very uneven and inconsistent. That MC is new. It shouldn't need that much force to move the piston, should it?
I have a new MC on the way from Hydratech. It will be interesting to see how much force it takes to move the piston on that one.
BTW, I replaced the previous MC because the piston was getting hung up as the piston returned. That was obvious when I was bleeding the brakes when I switched to Wilwood brakes.
I just started the car on the lift with full weight on the wheels. The power steering works now too. It seems that the seized MC interfered with the Hydroboost fluid bypass to the R&P.
One of the fixes I tried to solve this problem was to increase fluid flow with the PS pump flow control valve that came with the new pump. According to Jim Shea's notes, it probably flows about 4 gph with more than necessary pressure. I'm going to put the previous flow control back in (heavier spring and narrower throat, flows about 3 gph).
I just started the car on the lift with full weight on the wheels. The power steering works now too. It seems that the seized MC interfered with the Hydroboost fluid bypass to the R&P.
One of the fixes I tried to solve this problem was to increase fluid flow with the PS pump flow control valve that came with the new pump. According to Jim Shea's notes, it probably flows about 4 gph with more than necessary pressure. I'm going to put the previous flow control back in (heavier spring and narrower throat, flows about 3 gph).
I have brake / steering problems with my hydroboost set up! I am thinking it is the PS pump. Where did you get a high volume unit? I am ready to rip the sh*t off!
I removed the MC, and that removed brakes from the equation. Then I tested the power steering. It worked great, thus isolating the problem to the MC.
If that had not worked, I was going to bypass the HB and go right from the PS pump to the PS.
As chevymans 77 said, "May be time to isolate each component in the system and remove one at a time from the equation." Have you done that yet? If so, what did you try and when was the result? Do you have HB with stock steering or another steering system?
just do this... loosen the 2 nuts that hold the MC to the HB, put a 1/8+" gap in it... your lock up will go away...
Yup, I agree, due to some shituation here, I had to change out the pistons/seals in my m/cyl, and the depth of the divot in the piston was not exactly same as on the old one.....but everything else was fine...brakes were too sensitive, I put two washers on each side between the m/cyl and the HB unit.....much better
for ME, the issue was that the brakes tended to be too sensitive, almost no pedal travel before application.....the fender washer total thickness is a tad less than 1/8 inch per side....maybe .1 .....and since my issue was caused by a total mismatch of components, there is no direct correlation to your shituation, except vaguely similar symptoms.....
Yup, I agree, due to some shituation here, I had to change out the pistons/seals in my m/cyl, and the depth of the divot in the piston was not exactly same as on the old one.....but everything else was fine...brakes were too sensitive, I put two washers on each side between the m/cyl and the HB unit.....much better
for ME, the issue was that the brakes tended to be too sensitive, almost no pedal travel before application.....the fender washer total thickness is a tad less than 1/8 inch per side....maybe .1 .....and since my issue was caused by a total mismatch of components, there is no direct correlation to your shituation, except vaguely similar symptoms.....
The MC is brand new. I shouldn't have to mess with the piston/seals. i'm returning it for a refund.
06-18-2017, 08:28 PM
YUP!!! furr sure......jeez.....
:cheer s:
