Leak onto brake issue pulsation happen

[Mary]

Got a Chevy Blazer 2001 replaced rear axle seal next the pinion and then had the whole back end replaced. Still is something leaking onto brakes causing it to have this pulsation feeling under the brake pedal after driving for awhile then it keeps happening as it leaks onto brakes. Is very costly at this point and very annoying wondering when will it happen? Does not have a parking brake all the parts to it were taken off for some reason could this be the cause and how costly is it to replace the parking brake parts again? Someone mentioned ABS Sensor causing it or even the bearings or the drums causing this leak? Very frustrating got it repaired by 2 shops then a friend who is a mechanic replaced the back end for half the price still alot though. He mentioned had a problem and had to get another part but failed to tell me what it was. At one shop they showed me the seal was pounded on around it so they cleaned it off and replaced the seal they said that was causing the leak but it continued to do same thing like it still is now.

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[Mike]

You’ll have to identify what is leaking into the brake drums.

You replaced an axle grease seal, but that doesn’t mean the axle shaft itself is in good shape and allowing the seal to do its job. Have the grease seals in the drum been replaced?

If it isn’t grease, then it might be a brake fluid leak, most likely at a rear wheel cylinder. Is the brake fluid level in the master cylinder going down, how does the brake pedal feel when pressed?

It’s also possible that a shock absorber could be leaking enough oil to wet the brakes, but that would be unusual, and anybody who’s worked on your truck so far should have picked it up.

As for the parking brake, you could probably get most of the major hardware at a salvage yard, but I would get new springs, retainers and those little fiddly bits instead of using second hand pieces. Hardware kits aren’t expensive.

[Paul]

rub finger on what ever is leaking if it is rear axle oil it has a smell that you will not mistake for anything else.
I do not think anything leaking on rotor would cause a pulsation in braking
rotor itself could be warped (replace rotor)
or like the other person mentioned it could be abs sensor activating which causes a pumping the brake motion (pulsation)

I hope this helps you out a little

[Mechmann]

Most brake pulsation is caused by warped or rusted rotors. They can be replaced or taken to a machine shop to see if they can be resurfaced. See Eric’s video on his brake rotor/drum lathe. So you might try that next. A leak would probably just cause them to be less effective but not necessarily cause pulsation.

[Author]

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