Hydratech Hydraboost and brake bleeding problem

[1969CamaroRS]

My issue is as follows:


Brake bleeding issue with Hydraboost (shallow style master cylinder for 69 Camaro).
Car is 69 Camaro, Hydroboost from Hydratech, C5 Front Disc/Rear Disc brakes from Touring Classics, CPP MCPV-1 master cylinder (with adapter for shallow M/S).
Its completely new system. New Lines, Master and Hydroboost unit.
P/S lines are not connected nor has the car been run and had the PS purged of air.
Primary (closest to the Hydroboost) feeds the rear brake lines and secondaries (furthest from the hydroboost) feed the front brakes lines.
Master cylinder bench bled, has good streams of brake fluid out the primary and secondary on the bench.
Master Cylinder mounted to Hydroboost on car has no fluid coming out the primary, and very little coming out the secondary.
Brake pedal travel is very limited 2-2-1/2". I think it should be almost double that.
Pedal feels like it is stopping hard, there is no give nor does the pedal drop when a bleeder screw is opened.
Pedal also sticks and sometimes does not want to come up. It isn't smooth on the return.
Measured Hydroboost pushrod to M/C pushrod clearance running about 0.050" clearance (aimed for 0.030-0.060")




Seems like I can't depress my pedal enough to depress the M/S piston to push fluid down the lines (least the rear / primaries). Tried for over an hour to manually bleed (slowly push down pedal then open bleeder screw and close then slowly release pedal), no fluid was flowing down the primary to the rear lines. Tried gravity and vacuum bleeding as well no luck.


Any ideas?

Thanks a bunch!

[MuscleRodz]

Have you checked your adjustment at the brake pedal and is adjusted to where the booster is not already depressed? Do you have the rod in th upper or lower hole on the pedal?

[1969CamaroRS]

Thanks for the reply.


Have you checked your adjustment at the brake pedal and is adjusted to where the booster is not already depressed?

Yes, I believe I have about 0.050 of free play. Measured with the M/S off and I can feel a very small amount of free play in the pedal.


Do you have the rod in th upper or lower hole on the pedal?

Lower hole. My understanding was the top hole was for Manual brakes. So the rod is fairly straight and if I put it in the top it would have to be pretty far up out of alignment.


Thanks again.

[Roadbuster]

Lower hole. My understanding was the top hole was for Manual brakes. So the rod is fairly straight and if I put it in the top it would have to be pretty far up out of alignment.
Thanks again.

From the paperwork that came with my hydroboost: "NOTE: This system is designed to connect to the brake pedal in the uppermost of the two petal rod connection points usually found on most pedals."

Granted this is a hydroboost kit for an A-body, but double check your documentation to see that you have the mechanical connection correct.

Jon

[MuscleRodz]

Thanks for the reply.



Yes, I believe I have about 0.050 of free play. Measured with the M/S off and I can feel a very small amount of free play in the pedal.



Lower hole. My understanding was the top hole was for Manual brakes. So the rod is fairly straight and if I put it in the top it would have to be pretty far up out of alignment.


Thanks again.
Top hole is for manual brakes and alot of the hydroboost kits use that hole unless you have the 17* bracket that angles the booster like a vaccum booster is.

[pchdrive]

We installed a hydratech hydroboost system in our 69 Firebird. With all new components (disks, pads) in our case the setup of the rod to the pedal was supercritical. 1/4 to 1/2 turn makes a big difference.
Sounds like you might alos have all new components as well. We actually were preloading the brake system which made driving the car, well, darn near impossible.
Try cracking a fitting in the rear to see if fluid comes out with any pressure. If so you are already in a preload condition.
Even after adjustment you are not going to have alot of pedal travel.
Lastly, I cannot say enough good things about Paul at Hydratech. Call him, he will work with you and get it resolved.

[1969CamaroRS]

From the paperwork that came with my hydroboost: "NOTE: This system is designed to connect to the brake pedal in the uppermost of the two petal rod connection points usually found on most pedals."

Granted this is a hydroboost kit for an A-body, but double check your documentation to see that you have the mechanical connection correct.

Jon

I'll definitely double check the docs on that point, thanks.


Top hole is for manual brakes and alot of the hydroboost kits use that hole unless you have the 17* bracket that angles the booster like a vaccum booster is.

I'll try the top hole see how that works. It looked wrong but maybe would explain my problems. It didn't feel like I was compressing anything but it would make sense if it was preloaded. Thanks.



We installed a hydratech hydroboost system in our 69 Firebird. With all new components (disks, pads) in our case the setup of the rod to the pedal was supercritical. 1/4 to 1/2 turn makes a big difference.
Sounds like you might alos have all new components as well. We actually were preloading the brake system which made driving the car, well, darn near impossible.


Yep completely new braking system, lines master, and hydroboost unit.



Try cracking a fitting in the rear to see if fluid comes out with any pressure. If so you are already in a preload condition.
Even after adjustment you are not going to have alot of pedal travel.
Lastly, I cannot say enough good things about Paul at Hydratech. Call him, he will work with you and get it resolved.

Yeah I actually cracked each fitting on the rear line (I have a 2 piece rear line). I had a little fluid dribble out of the union at the frame rail, no fluid at the hump over to the diff.

I doubt any fluid is getting out there, I mounted the M/S up on the hydroboost but didn't connect the brake lines instead left the bench bleeder fittings in and the hoses up over to the reservoir. That way I could see what volume of fluid was being passed. There was 0 fluid going to the rears and very little fluid going to the front.

I called Frank at Prodigy (who I bought the unit from) and he was going to get me in contact with Paul to see if we could figure it out. Thanks.

[pchdrive]

I went back to review the installation procedure.
A couple points:
1. "The system is designed to connect to the brake pedal in the uppermost of the two pedal rod connection points. Rod angle between the brake assist unit and brake pedal should be as straight as possible".
2. Silly question perhaps, But did you also connect the lines to the PS pump (with brass T return straight in line), fill the PS reservior (with Valvoline Synpower, prevents foaming), crank the engine and purge the PS system of air bubbles?
Instructions are clear to do all this first before depressing the brake pedal.

[Josh]

All I can say id Paul is the Man. Talk to him.

[1969CamaroRS]

I went back to review the installation procedure.
A couple points:
1. "The system is designed to connect to the brake pedal in the uppermost of the two pedal rod connection points. Rod angle between the brake assist unit and brake pedal should be as straight as possible".
2. Silly question perhaps, But did you also connect the lines to the PS pump (with brass T return straight in line), fill the PS reservior (with Valvoline Synpower, prevents foaming), crank the engine and purge the PS system of air bubbles?
Instructions are clear to do all this first before depressing the brake pedal.

Sounds like I should read the instructions again. P/S lines are not connected nor has the car been run and had the PS purged of air. I thought I read where I could bleed brakes w/o connecting the hoses for the P/S. That w/o the Hydroboost in the system it would be like manual brakes. Thanks a lot.


All I can say id Paul is the Man. Talk to him.
I'm hoping to hard man to ahold of.

[1969CamaroRS]

I believe I solved the problem. I had the clevis from the hydroboost mounted on the bottom hole on the brake pedal when it needed to be mounted on the top hole.

My brake pedal switch was adjusted all the way out which made it difficult to mount on the upper hole. But once I adjusted the switch all the way out, I was able to mount it on the upper hole

Now I get full pedal travel and a steady stream of fluid out both the primary and secondaries. Still got to bled the rear brakes but should be be able to now that I can actually push fluid out the master cylinder.

So to recap:

Read the instructions again ;)
Hydroboost mounted to upper hole on brake pedal
Adjust brake pedal light switch all the way out until you get things mounted then adjust as needed.



Thanks for all the replies and help!

[LONE*STAR]

Ahhh... the mysteries of the ever elusive Hydra' boost.

[MonzaRacer]

and everyone wonders why I like to reverse bleed systems,,,,