LS1 Hydroboost fluid leakage problem

[Bridar]

Hi, I followed you guys over for some help.

I have the BMW Hydroboost installed on an LS1 with the Porsche power steering rack. The problem I have is that the stock LS1 PS Reservior doesn't seem to be large enough. With the engine running, I can put enough fluid into the reservior to keep the bottom of the reservior wet, but after the engine has been off for several days the pressure in the hydraulic accumulator (aka...the "bomb") on the hydroboost system relieves itself into the reservior and it overflows the tank. I would just put a larger tank on, but there is no room! Has anyone encountered this before and what did you do to resolve it?

Thanks.

[v8carreragts]

I have the original BMW resivoir on mine. I did re-configure some of the tubes on it though.

[Bridar]

looks like you are running an SBC. I have an LS1 so the PS Pump is on the driver's side. I also have an 968 chassis so there is not the room that you have to mount the talll BMW reservior.

thanks for the reply, though.

[Dawgz83948]

There has to be something wrong with your car. I'm using the stock LT1 reservior and keep the fluid filled to where it barely kisses the bottom of the dipstick on the cap. I've left my car off for weeks and no fluid seeps back into the reservior. If I do pump the brakes while the motor is off it spews fluid everywhere since it is also too small for the BMW system. Either you Booster is allowing fluid to travel through it (bad O-rings) or the proportioning valve is bad (not likely but possible).

[Bridar]

I suppose it is possible that the booster is bad, but I am doubtful since I replaced the seal and all of the o-rings. (it was leaking PS fluid out the bottom when I first mounted it).

I have experienced the brake pedal spewing scenario that you described with your LT1. At least that tells me that mine is behaving similarly to a known "good" system.

To be honest, I cannot be completely sure that I did not push the brake pedal at some point when the engine was off for several weeks.

I am now working on a design for a surge tank that may help to control some of that leakage, but another thought crossed my mind: Why not remove the accumulator and plug the port on the priority valve? My logic is that the accumulator is only used to provide power brakes in an engine-off condition. But with a vacuum boosted system you don't have power with the engine off either. Has anyone tried this on the hydroboost system?

[v8carreragts]

But with a vacuum boosted system you don't have power with the engine off either

Not true. Vacuum systems have at least one application with the engine off. There is storred vacuum in the booster.

I'm not sure that the system would work properly without the accumulator.

[Dawgz83948]

What port are you wanting to plug again? Ohh remove the bomb and plug it, I don't know, let me know how that works out. Personally I'd rather have a mess on my hands than no brake on the freeway if my motor dies.

[Bridar]

Removing the accumulator and plugging the port would be no different than if you had an accumulator with a blown diaphragm or that lost its nitrogen charge. You would still have brakes, but they would be non-boosted (e.g....manual).

I may try plugging the port if my surge tank idea cannot be worked out. I really don't want to settle for a system that occasionally blows PS fluid all over the place. Besides, I typically try to only drive with the engine on:rolleyes: