Birf Job Complete....Front Brake Problems??

[General]

Well, I completed my first front end birf maintenance on Saturday. Thanks for the great $ and delivery on the parts, Dan. Everything went as planned & it took most of the day on Sat. I replaced all wheel bearings & races, trunion bearings & races and rotors w/100-series pads. Yes, my axle oil seal was comprimised & the birfs were filled with first-class goop. I replaced with the recommended synth wheel bearing grease, moly birf grease & synth diff gear oil.

I drive 25 miles from my brother's garage to my home after the maintenance work was complete. I checked my hubs & rotors when I got home....hubs were warm (what I expected) and the PS rotor was also warm....but, the DS rotor burnt the skin on my finger tips. Wow! So, I let it cool down & pulled the DS wheel only to discover that the rotor/hub would spin freely. Yes, I set the hub preload to ~8 lbf using a spring-scale....so, I don't think anything is wrong with the hub or wheel bearings. Of course, during the rebuild, I had to depress the caliper pistons using a "C" clamp and the old pads. The brake fluid reservior did not overflow....it just filled up nicely to the rim with the cap removed. I put wheel back on & drove it 30 miles yesterday & still, I have a very warm DS rotor (untouchable). No, I don't ride the brakes.

My current thinking is that maybe I checked the wrong caliper/hub. Could the PS caliper be "stuck" therefore making the DS caliper do all the work? The rig doesn't pull to either side when braking.

Ok.....gimme your $.02. And, sorry for the long post.

 

[elmariachi]

The pads do ride against the rotor, so I would think a rotor would be well over 140 degrees and very hot to the touch even with everything working properly, though I sure have never touched one to see. My advice would be to pull that wheel, jack up the truck and see if the wheel still appears to be moving freely. But with a helper pushing the pedal slightly and you with your c-clamp and the caliper removed you should be able to rule the caliper out quickly by checking piston movement. The only other source of heat, as you indicated, is if the bearings are not properly seated and tightened.

 

[Riad]

You may also want to bleed the brakes. If either of your caliper brake lines is twisted, the performance of either or both caliper(s) will be degraded. It happens due to the twist in the line. After doing a birf job, you may have put the caliper back with twisted line. Eitherway, if bleeding brakes does not resolve the issue then definitely some thing else is wrong. When it happened to me, I only bled the front lines, left the rears alone. It has been fine for 5K miles now.

 

[IdahoDoug]

Confused here. You said (as though it's a problem) "only to discover that the rotor/hub would turn freely". Is this the case, or a typo? If it turns freely then all is well and it's just your new rotors and new 100 series pads - a known brake drag issue until they're broken in.

DougM

 

[General]

You may also want to bleed the brakes. If either of your caliper brake lines is twisted, the performance of either or both caliper(s) will be degraded. It happens due to the twist in the line. After doing a birf job, you may have put the caliper back with twisted line. Eitherway, if bleeding brakes does not resolve the issue then definitely some thing else is wrong. When it happened to me, I only bled the front lines, left the rears alone. It has been fine for 5K miles now.

Thanks for the reply. No twists.

 

[General]

Confused here. You said (as though it's a problem) "only to discover that the rotor/hub would turn freely". Is this the case, or a typo? If it turns freely then all is well and it's just your new rotors and new 100 series pads - a known brake drag issue until they're broken in.

DougM

Not a problem....I just expected there to be "some" drag due to the heat. I did, however, observe a gap large enough to slide 2-3 pieces of copy paper between the rotor and the brake pad.

 

[General]

Any More Ideas??

I'm surprised at the lack of feedback....

 

[elmariachi]

I'm surprised at the lack of feedback....

Have you removed the caliper and inspected piston and pad movement? If the pads are not touching the face of the rotor, they could be hanging up because of either issue. Either the 100 pads are not moving smoothly inside or the pistons are not working right.

 

[General]

Yep, I checked both. Pads & piston are moving just fine. I think my rig is OK. I'll watch it over the next couple of days.

 

[concretejungle]

I think you are fine. Just keep you eyes on it and see if one wheel accumulates more brake dust than the other.

 

[vcheng]

Thanks for the reply. No twists.

Sometimes, it may not be an apparent external twist. Internal degradation is the flex hose can result in a one way check valve type of obstruction that can lead to the pad pushing against the rotor.

I am assuming that you lubricated the caliper slide bolts on both sides and that the 100 series pads are a good OEM type fit.

 

[Rich]

It is abnormal for one brake rotor to be much hotter than another on the same axle. Something is definitly not right.

Very likely that the hot side has a sticking piston.

If the cold side was cold because it was not working, I would expect a signficant pull to the opposite side during braking.

 

[General]

Yes, I would expect a pull too. I'll keep an eye on it.