Brake Bleeding Issues / MC trouble?
 

Welp, I have been bleeding brakes all day with no success. All the little bubbles are gone and the fluid runs solid at each caliper BUT... my pedal is as soft as mashed potatoes.

Additional facts:
1. When pump bleeding the rear calipers, once the caliper is bleed the pedal drops to the floor. This is not the case with the fronts. The pedal doesn't drop to the floor at all.

2. When you hit the brake (even as soft as they are) the rear brakes engage. This is not the case for the fronts. It takes a second pump to get them to engage.

Theory one: After using the Motive power bleeder for about 5 cycles and good old two person pump the brake pedal technique about 5 cycles there might still be air somewhere in the lines or MC.

Theory two: The MC is screwed. A friend think that because I had it completely empty for several months one of the seals is ruined.

Additional theories ????

Fact 1 and fact 2 are contradictory. One says the rears don't work and the fronts do. Two says the opposite.

The MC contains a dual hydraulic circuit that divides the front and rear system. If only one of the above is accurate, I would say either the front or rear piston seal is torn (leaking). This can occur during manual bleeding and the brake pedal (piston) is allowed to exceed the normal pedal travel.

This happens quite frequently if the pedal travels too far.

Sherwood

Did you do anything prior to the flush? That is to say remove the calipers and rebuild them? If so check that they are on the correct sides and the bleeders are pointing up. if so on to the next common item.
If you rebuilt the calipers with new seals you might be getting too much piston pull back. Easy fix to this. Remove one pad and pump the brake pedal just enough to make the piston move in so the pad will no longer fit back in. Now move the piston out just enough to slide the pad back in with some friction from the piston.
i like to use the pad to wiggle the piston back and the push the pad in as soon as I can force it by hand. Do this to each pad on each caliper that was rebuilt.

The rears work with only one pump and the fronts work after two pumps of the pedal.
The rears allow the pedal to drop to the floor when bleed. The fronts do not allow the pedal to drop to the floor when bleed.
BUT fluid comes out solid on all calipers when bleed. The pedal is very very soft.

Sorry for the confusion.

Sherwood, How do you avoid this from happening when you manually bleed the brakes? Should I put something under the pedal?

Green... Now that I think about it I think the bleeders are on the bottom on both front brakes.. I didn't realize they could go on backwards.. Do you think that might be the issue?

All calipers where completely rebuilt by PMB Performance. They came back like new.

This may be your issue as I was taught by my shop that new calipers need to be "exercised". Also bleeders on the fronts are upside down, sorry I missed that on 1st look, fix that!

I assume you have pad spreaders and some old worn out pads? Put the old pads in a caliper (I started with RR as it's furthest away from MC, just like bleeding). Push the pads back as far as they go using the spreader tool. Now pump your brake pedal until they lock that wheel and are both fully against the rotor. Repeat this 5 times then move to the next wheel and repeat. Now do a full bleed and see what you get. HTH

Hope this helps,
Sherwood

I've found that walking away and waiting a day or two helps get rid of all the bubbles. Tapping the calipers with a rubber mallet is good Mojo....

I will assume that the calipers were installed with the nipples at the top?

Alright!!! Step one reverse the front calipers and see what happens..
I'm sure I will be coming back to this thread... Although it would be great it that is the only problem.

So....de nips b on de bottom?

:eek:

They are for sure... I'm not a mechanic... I don't even play one on TV :D

Common mistake, that's why I asked. Eric should include a "Hey, Stoopid" note when he returns calipers......

Good luck.

You aren't alone... There are a LOT of members of the "Upside Down Caliper Club!"

JB

If they are pointing down I can assure you without question this is a problem.
Be glad it is a simple fix and not the MC.

With rebuilt calipers all around, be sure to do the pad reset trick after flipping the front calipers upright. You will get a firm pedal right away and not deal with a 100 miles of mushy brake syndrome.

AWESOME!!! Reversed them and they are working perfectly.

Gud 4 u.....

Joe Bob.......I love to give a good nip on the bottom...especially the Wife's...:D:D:D:D:D:D