Brake bleeding issue

[RBBJ 32 HOTROD]

I went to bleed my brakes today, I used my pressure bleeder left over from my BMW. It was able to screw onto the reservoir no problem. I got all the air out but the pedal still able to go to the floor. When I pushed the pedal the front brakes calibers worked fine. The rears did not work well(was still able to spin the rotors.
I noticed when I pressed the brake pedal that the rear master cylinder rod went all the way in while the front did not. It's almost like the fluid is not pressurizing. Has anyone had this issue?

[FF33rod]

Sounds like the rear brake circuit still has air. what makes you think it doesn't?
Steve

[RBBJ 32 HOTROD]

When I had it pressurized with the pressure bleeder it only had fluid coming out but I can bleed them again and see. The pedal just never got hard.

[NAZ]

If you are using the Wilwood dual M/C pedal assembly with the bias adjustment, make sure that you have set the gap correctly on the balance bar. This is probably not in your FFR manual but is supplied with the Wilwood pedal assembly and can be obtained from Wilwood. This is import as it affects safety. Also, ensure you have adjusted the piston rods so that you get full travel before the pedal hits the floor. And, the piston must fully retract when you release the pedal.

Next is the caliper orientation. The bleeder must be the highest point for all the air to escape. Depending on how your calipers are mounted you may have to unbolt them and rotate them on the rotor until they are at the highest point. This would require either a helper to hold the caliper in this position or safety wire them so they don't get bumped and fall off the rotor.

Personally, I prefer to vacuum bleed brakes and use solo bleeder valves to make it a one-man operation. Solo bleeders have a check valve so that air cannot be drawn back into the caliper. Vacuum bleeding is the same basic principle as pressure bleeding but uses atmospheric pressure to force the fluid out the bleeder valve, leaving the reservoir open to check fluid level. Pull a vacuum and watch the fluid level drop and use the bleeder valve to adjust the flow rate so you can keep up with topping off the reservoir.

Many will tell you to bench bleed the M/Cs -- I have yet to find this necessary using my method but whatever method you prefer is OK if it works.

[Packer fan]

It may also be a bad master cylinder. I had that problem with one of mine. I believe the symptom I had was that with the reservoir full when I stepped on the pedal the level went up.

[JimLev]

RBBJ, did you put any fluid in the MC before you put the caps on? I used my pressure bleeder (probably same as you have, BAVAuto) as well as a vacuum at the calipers.

[RBBJ 32 HOTROD]

RBBJ, did you put any fluid in the MC before you put the caps on? I used my pressure bleeder (probably same as you have, BAVAuto) as well as a vacuum at the calipers.

Jim I bench bled on the car prior to pressure bleeding it.Yes I did use my bleeder from BavAuto. Lol

[Jacob McCrea]

It may also be a bad master cylinder. I had that problem with one of mine. I believe the symptom I had was that with the reservoir full when I stepped on the pedal the level went up.

For what it's worth, I also tremendous problems getting my rear brakes firm. I tried gravity bleeding, a Mityvac tool, and a Phoenix Systems reverse bleeder, and probably put a half gallon of fluid through the system with no success. I eventually took off the Wilwood master, completely disassembled it and cleared all the orifices. As far as I could tell, there was some manufacturing debris in an orifice or passage that was preventing the bore from completely refilling with fluid after each pedal stroke. It firmed up quickly after reinstallation. Hope this helps and good luck.

[HVACMAN]

I agree with NAZ. I have the six piston Wilwood's front and single piston Cobra's rear. I used a relatively inexpensive vacuum bleeder from Amazon that has a bottle that keeps the reservoir full, so you don't have to keep checking. I was through in about thirty minutes and the pedal is firm.

[RBBJ 32 HOTROD]

Thank you Jacob I'll look into that.

[RBBJ 32 HOTROD]

How high is everyone mounting their reservoirs? My m/c are not being replenished by gravity feed.

[NAZ]

Can't use mine as an example, I mounted my M/Cs 3" lower than FFR made brackets for. But I suggest that if you ever plan to use a hood then measure the clearance and place your reservoirs as high as you can.

[HVACMAN]

I'm not using the hood but I wanted them as high as possible.IMG_0123.JPG I think this where the hood pin usually land.

[RBBJ 32 HOTROD]

Thanks guys. I think I'm going to mount it about where they did on the model at FFR.

[RBBJ 32 HOTROD]

I ended up ordering a new dual reservoir from speedway motors.

[RBBJ 32 HOTROD]

I just noticed today that I have plenty of fluid flow when bleeding the rears but seams like no pressure, the pistons dont even move on both rears. The calipers are brand new, came in a disc brake upgrade for the rears from The Right Stuff. I'm thinking a m/c issue.

[JimLev]

Are you expecting the the pistons to show movement while you have the bleeder open?
They need to be closed in order for them to move.

[RBBJ 32 HOTROD]

Are you expecting the the pistons to show movement while you have the bleeder open?
They need to be closed in order for them to move.

After bleeding them before I've pumped the brakes and the fronts lock up but the rears dont. You can still wiggle the pads while they pressed.

[NAZ]

Do you have the Wilwood dual M/C & balance bar pedal assembly?

[RBBJ 32 HOTROD]

Yes I have the Wilwood dual m/c's. I'm always wondering why they have you cut 5/8" off each threaded rod and in the manual it says to make sure the 90* is pointing up when tight but in pictures of doing the hard lines they point to the left. Mine are to the left so the lines can go that way.

[NAZ]

Did you set the gap between the large clevis washers and the side of the pedal to .020"-.025" like directed in the Wilwood set-up instructions? If not, you may be loosing some stroke.

figure4.gif

[RBBJ 32 HOTROD]

I'm going to check it again tonight. I think I set it for. 20 for each side, so that would be like. 40+ total.

[RBBJ 32 HOTROD]

My new 5/8" bore m/c comes in today.