sparkwirez06

iTrader: (18)

I installed a FR rack and pinion, with a new gm type 2 ps pump, and a hydro boost. with a heidts control valve. I started the car, let the system bleed out the air, all seemed well. I put car on jack stands, ran in gear applied the brakes several times. shut it off and noticed the brake lights stayed on. played with the pedal(thinking it was a switch) still on. I started the car, applied the brakes, pedal got really hard and pushed up against my foot.
Fluid ran out of the ps pump, figured I blew out the seals in the pump,
I pulled the pump and it appears fine, ( possibly a bypass??)
All my lines are correct, I'm thinking maybe the rod in the hb is too long??
all parts are new and installed by me, except the hb unit. any ideas???

ryanleiker

iTrader: (2)

I'll have to double check how mine is hooked up, but I think your lines coming into and out of the hydro need to be switched from the rack and from the ps pump.

sparkwirez06

iTrader: (18)

My lines are correct, I have a heidts comtrol valve between the rack and the hydroboost. rack is clearly marked as return, and hb has different size fittings.
The first pics above.

ls1nova71

iTrader: (4)

With the engine running, if you turn the wheels does the brake pedal move down without pushing it? I had one kick back like you described and it moved on its own. Turned out to be a bad/sticking valve in the HB. I replaced the HB and never had another problem.

sparkwirez06

iTrader: (18)

The high side in, coming from the ps pump, is next to the cylinder on the hb.
my hb is installed upside down( to keep lines on bottom) may appear to be wrong, but is correct.

sparkwirez06

iTrader: (18)

I can't find anything wrong, so that may be the problem, I can't run the car right now, I have the ps, pump off. thanks

ryanleiker

iTrader: (2)

Mine hasn't been run yet, maybe I need to check my line routing.

DW SD

I think the pedal to booster rod may be too long. In my HB unit I can hear fluid flowing to it when just a hair of brake pedal is applied (maybe 1/2" of pedal movement at the foot pad).
In my conversion i used a threaded rod and sleeve to adjust the rod length. I could actually use the noise of the fluid flowing to set the rod length. I made mine about 1/16" or 1/8" shorter than where I'd here the fluid flowing.

Aldo check clearance between booster and master.

Hope that helps.

sparkwirez06

iTrader: (18)

I think that may be the problem, I will check it out tomorrow, thanks

DW SD

Also check that HB unit doesn't apply preload to the master cylinder piston just by bolting the master cylinder to the HB UNIT. I think there should be a little clearance maybe 0.050". I used some play dough to check the clearance there too.

sparkwirez06

iTrader: (18)

thanks, will do, I did replace the master cylinder so that could be the problem.

DW SD

I made sure the master cylinder I selected came from a 3/4 ton vehicle equipped with hydroboost.
I had no problems with it bolting up or clearance between the rod and master cylinder piston.
BTW - I have a mustang II rack. I don't use the adjustable valve, but do use third party the volume control (reducer) adapter in the pump body.
I don't think hydroboost needs much hydraulic volume to operate. Bear in mind, you can get several braking sequences just on the hydroboost's accumulator alone (were the pump to fail).

I do not have a twitchy rack.

I selected that due to simplicity. I didn't like the idea of more high pressure hose ends, etc. Seems like more opportunities for leaks.

Doug

unnatrl

iTrader: (1)

I second this. Mine slowly applied pressure (took about a mile) until it locked the front brakes up. I had to open the bleeder screw and let brake fluid out. About a mile later same issue. Replacing master cylinders didn't resolve it. Swapping hydroboost units fixed it.

DW SD

If you need to buy a new unit, after hunting a lot, I bought a brand new AC Delco unit on Amazon for a 2010 silver ado. It was $137. Not some rebuilt POS dipped in black paint.
I think the units all are virtually the same.
EDIT: here is the unit I bought: Doug

sparkwirez06

iTrader: (18)

I put the pump and the lines back on today, put in some fluid and turned the rack from side to side, oil came out just as before, I pressure checked the res, and the pump and found no leaks,???? I put the res on the pump with the fitting and put pressure on the return, oil came out around the hardline banjo fitting( need crush washers??) not really, the line runs around the back of the pump and crosses over the ps pump mount, there was incorrect angle on the hardline, causing it to twist, resulting in a leak!!! I will still increase my hb rod clearance just to be safe.
I ordered a new line and res tank from summit, I didn't want to be with out parts if I had a problem. I looked all day for 16mm copper crush washers
without finding any, ordered back stock from McMaster carr just to be safe. I'll just send the summit stuff back. If anybody uses the vintage air lines make sure you have clearance. thanks
yeah,I put the line in a vise and bent it to clear!!

dirtymoe77

iTrader: (2)

Doug,

Would you happen to have a part no. for that? Or an Amazon link?

sparkwirez06

iTrader: (18)

what? for the hardline? VTA852000, summit racing

dirtymoe77

iTrader: (2)

Post 14...Doug said he found a Hyrdoboost for $170 brand new

sparkwirez06

iTrader: (18)

Was no problem with any parts, just the hardline got 2 washers from local machine shop. was normal pressure just the hardline being in a bind allowed it to leak.

DW SD

Actually.... I looked it up. $137 brand new. The price adjusted a bit up, now. Still a great deal, I think.

Doug