Pulling to the left when braking...

Hello All - First time posting…Sorry for the length of the post...

I've been having an issue with my brakes pulling to the left when applied after replacing the front brake rotors and pads (old ones were worn out). At the same time I decided to installed YJ brake lines and flush the old brake fluid out. Did the flush process by sucking the old fluid out of the master with a vacuum pump (making sure I didn’t pull all the fluid out) and filled with new fluid. Bled the brakes starting from RR, RL, FR, and then FL. Test drove and that’s when I noticed the pull to the left. After about a 30 mile test drive, I notice that the pad contact on the pass side was only at the top of the rotor vs. the driver side which showed full pad contact (only seen from the outside), telling me that the left side was doing all the work.

‘95 XJ with 4.5" lift (Ironman 4x4 upper and lower arms and adjustable track bar. 31” tires, non-ABS. Brakes are stock except for the longer YJ brake lines.

Things I've tried to resolve this issue:

- Researched all I can on the web for brake pulling
- swapped tires left to right and front to back - no change
- check and adjusted tire pressure - all even
- check and tighten all UCA's, LCA's, and Track bar
- checked myself and had the TRE's and ball joints check by a local shop - no issues found
- swapped the pads from left to right - no change
- swapped the rotors from left to right - no change
- bled the fluid for a 2nd time - no change
- replace both brake calipers with new ones, replaced the master cylinder and re-bleed - no change (YJ brake lines are new – only about a week or 2 old)
- weld mod to the knuckles where brake pads contact and create a notch – found procedure on here.
- installed the stock brake lines – no change. Put the YJ brake lines back on.
- tried stock wheels and tires from another XJ - no change
- check alignment - 2 time now all within spec - no change
- Removed prop/combo valve disassembled and cleaned. Reinstalled and re-bled - no change
- removed the hard line from the prop valve to the front pass caliper and checked for blockage using compressed air - none found
- now I'm on my 3rd or 4th bottle of brake fluid from several bleeds


I’m at a loss with this brake issue. I have another new pass caliper I picked up I can try. I haven’t bled the prop valve. I read the prop valve mod on here somewhere which mentions how to bleed a prop valve. I can try that. I thought the prop valve didn’t have to be bled. I don’t have any experience with that – maybe someone can comment….

Not sure what else to try. If anyone has any ideas – please let me know.


Thanks for your help/comments….

Sounds like a new set of calipers and hardware would be a good idea.

Think of it like tractor brakes. You apply only the left and you turn to the left because that slows down more than the right. Apply the right, right slows down more. Either your caliper piston on the right is not applying fully causing the left to slow down more or the caliper hardware is not allowing it to slide.

My point exactly...

Take both calipers off, rotors too.
With a wire brush, clean up the knuckles where the pad rides on it until it's pretty shiny.
Now look for irregularities in the pad riding surface.
I bet they are jacked up where the pad backing now rides, causing uneven clamping pressure as one pad or another jams into the knuckle instead of gliding on top of it.

m4runner28 said:

- swapped the pads from left to right - no change

Click to expand...

You do know that the pads are side specific, right?

Ditch the vac bleeder. Use a pressure bleeder or just bleed with a helper on the brake pedal.

Talyn said:

You do know that the pads are side specific, right?

Click to expand...

??

location specific--inner vs. outer, I know..... side specific??

calipers, on the other hand, are definitely side specific-- make sure the bleeder valve is located on the top of the caliper.

Have you replaced the caliper mounting bolts and bushings?
Bent caliper bolts or badly worn bushings will cause the pads to ride unevenly, leading to uneven braking..

Another possibility is a bent knuckle.

Shorty said:

side specific??

Click to expand...

Yes. Take a look at the tabs on the pad that mount on the slide rails on the knuckle. One is missing the inner ear. That one goes on the top. So, you would insert the bottom first then pivot the brake caliper in to the top. The pads are usually stamper L or R.

Talyn said:

Yes. Take a look at the tabs on the pad that mount on the slide rails on the knuckle. One is missing the inner ear. That one goes on the top. So, you would insert the bottom first then pivot the brake caliper in to the top. The pads are usually stamper L or R.

Click to expand...

huh, I've obviously been really lucky in the past.... I've never seen that before. I'll have to check the last set I took off, 'cuz I swear they were the same from left to right.

That might make explaining why some pads fit better than others easier to do!

Post #2 is good. I've had calipers malfunction after a pad change because there was junk in the cylinder bore.

Yes, pads are side specific, refer to Talyn's notes.

The area where the pads ride on the knuckle should be smooth. I noticed you did a "Mod". If you did what you were supposed to do, it would be a "Repair" as you are fulling the divots and filing them flat again.

The proportioning valve is front to back, not side to side. It has 2 outputs for front brakes because that's a nice place to T the system. Ignore it for now.

I started vacuum bleeding when the old lady wouldn't get off the couch to push on the pedal. Works good ether way, just make sure you don't let air back into the system.

Speaking of air, make sure the bleed screw is on the Top of the Caliper. This is sort of like the brake pad thing, but more important

IIRC, the '95 uses the one piece knuckle. If you are using your old calipers make sure the sliders work (They are under rubber bellows). If new, they should work fine.

~Ron

And use disc brake lube on bolts,tabs the pads ride on,etc.

What is the deal with people lubing the bolts? That won't do anything. What you want to lube is the ID of the rubber bushing and the OD of the steel sleeve that the bolts pass through.