Well, now that life has calmed down a bit, I can get back to working on the ole XJ.

1987 Wagoneer, 4.0, AW4, D30, D35 for what it matters.

Experienced severe, random brake pedal kick back today on the way home from work. Brakes were fine all day, then it randomly kicked back. It seemed to be coming from the driver's front, and it was scary enough that I though I'd find the caliper dangling by the brake line, wrapped around the axle.

No such luck. Up on jack stands, both front wheels off and everything is "toight like a toiger". The only thing I could find, which needs to be addressed, but doesn't seem to be involved, is that somehow the dust boots for 2 of my 4 tie rod ends have come off...

The rotors have no grooves and to the naked eye don't look warped (I know I should have them checked), the pads are about 50%, all bolts, etc are tight.

Thought it might be in the pedal / booster mechanism, but the under dash parts and pieces look good. By the time I got under the hood, it was too dark to do any real looking.

Put the wheels back on and drove around, but couldn't reliably reproduce. It would happen under hard and soft braking, with no rhyme or reason.

Any thoughts? Should I be looking in the rear as well?

 

Yeah, check the rears. If the hardware has failed you might have a shoe riding places it shouldn't be.

 

Sounds like a caliper piston(s) is sticking in the bore.

 

Yeah, I think I'll pull those puppies off and take a look...really wish things would calm down so I could get elbows deep in her

Wouldn't that just cause the brake pedal to stick and not forcibly kick back?

Thanks for the suggestions!

 

When you say the pedal kicks back at you does it get real hard when it does it? If so check the vacuum to the brake booster.

 

Yeah, but it feels really hard, like something is pressing back on the caliper or drum piston, not like I lost power. It kicks hard enough to send my knee into the steering wheel. Was out at lunch listening a bit as I drove around the parking lot slowly. Hearing a definite dragging from the rear, so I think I borked something in the drums and need to take a look. That's my next COA.

Give me a day and I'll get back to y'all.

Thanks again for the suggestions!

 

There is a check valve on the brake booster the the vacuum line connect to. If the check valve is going bad it can cause the pedal to kick back and get rock hard. I had one do the exact same thing. But it shouldn't cause a dragging sound on you brakes. Sound like you may have 2 problems. Let us know what you find. If I were you I wouldn't drive it until you fix the problem. I would hate for you to hear you got into an accident.

 

Good to know - I'll definitely take a look there.

All I have to do is make it home from work, then it gets parked. Brake issues freak me out. I've only had it bad once. I was moving my 1949 Plymouth Special DeLux to storage and had the pedal go to the floor on me. Totaled it.
I'm very wary when it comes to brakes...

 

This *might* be the issue...

 

/t

 

Looks like its time for some new shoes!