SparkyJJO

iTrader: (11)

So I put new rotors and pads on the front, and a new caliper and hardware on the front driver side (again, already did it once a year ago but that side was dragging again, causing the warped rotor). I had replaced the hard line and soft line this past winter.

However, I still have brake shudder as if the rotors are warped. But, not consistently. Sometimes I put the brakes on and it is smooth as can be, other times it shakes like it did with the old rotors and pads

What am I missing? Could it be my ABS block giving me grief somehow? When I replaced the hard line I replaced everything except the flexible part that goes into the ABS block (since I couldn't find a replacement flexi part).

Any help would be appreciated.

SparkyJJO

iTrader: (11)

I'm probably the only one with this issue, aren't I.

SparkyJJO

iTrader: (11)

Seriously, no input at all?

I hate to keep throwing parts at this problem without knowing what it is, but maybe I should just replace the ABS block and see what happens?

SparkyJJO

iTrader: (11)

<sigh> nobody at all

pace

I've still got some shuddering problems, but haven't addressed them yet, so can't really help you out. Probably wouldn't help, but have you tried flushing the fluid?

Foxxtron

iTrader: (1)

Were the rotors and pads bedded in properly?

EDIT: Also has the ABS module been properly reset, then going back to ensure there's little to no air in the brake lines?

chavez885

iTrader: (12)

I assume since you had the calipers off the brakes have been bled. Try disabling your ABS and see if it the shuddering goes away. (you can pull your abs fuse to disable it)

SparkyJJO

iTrader: (11)

Yep bedded them according to mfr directions. I bled out all the old fluid as well.

How do you "properly reset" the ABS? I just swapped the caliper and bled the line to get the air out of the caliper and flush the old fluid out.

I'll try pulling the ABS fuse and see if that seems to make any difference.

I was wondering though if I have some blockage (bad solenoid perhaps) that is making that hold pressure randomly. Or something like that. Maybe that's stupid but I'm kind of at a loss.

thanks for the help so far, I'll report back what I find.

Foxxtron

iTrader: (1)

Two ways to reset the ABS module.

1. Get access to a Tech2 (dealership forbidding) to electronically reset the module.
or
2. Take the car to a safe area where you can "trigger" the ABS module by temporarily "slipping" the wheels.

The purpose of triggering or resetting the ABS module is to ensure there is little to no air trapped behind the valves of the ABS module. It may not solve your problem, but I figure it's something to perform to rule out the possibility.

SparkyJJO

iTrader: (11)

Well the ABS has been triggered before and hasn't affected anything. Shouldn't be any air in the ABS block, ABS triggered several times this past winter and I didn't get any air in it when I replaced the caliper.

Foxxtron

iTrader: (1)

When you did replace the caliper, did you ensure that it was bled properly? Also, was the caliper a remanufactured one or a brand new OEM (many remans have been known to have spread calipers)? Even if the caliper is okay, have you checked the caliper sliding pins to see if they're properly lubricated?

EDIT: the caliper mounting bolts could also be another thing to check as well.

If so, have you attempted to inspect the runout on the rotors and check your hubs? (believe it or not, sometimes debris on the hub face that becomes trapped between rotor and hub can cause for an improper fit)

If those are okay, then you should also check the control arms bushings and ball joints to see if they're okay. As hard as it seems to perceive, sometimes loose and/or worn control arm bushings and/or ball joints can cause this type of problem.

Again, just running over some local areas where the problem may exist.

SparkyJJO

iTrader: (11)

Bled it twice. It is a reman, but I've now replaced it twice (once when the original seized up, and again under the lifetime warranty of the reman). Slide pins move smoothly. Caliper bolts are new.

Lower control arm bushings replaced a little over 1.5 years ago, uppers replaced just recently. Ball joints are original but there isn't any play in them.

Runout on the rotors? Not sure exactly what you mean (I feel dumb right now not knowing lol). Hubs were cleaned off before I put the rotors on.

I'm taking a 55 mile round trip tomorrow so I'll pull the ABS fuse for that and see if that makes any difference at all. Not like I'll hit any snow or ice to worry about needing ABS anyway

Hm one thing I did notice when I put it all together on the driver side: as I spun the spindle by hand with the rotor on it and the caliper put on it would go swoosh, swoosh as it went around, like the pads were making very light contact with the rotor at some point in each revolution. I thought that odd but couldn't find anything wrong. Perhaps related?

Foxxtron

iTrader: (1)

Sorry for not getting back sooner.

Runout is the amount of "non-parallel" brake rotor friction surface area. It's usually measured with a dial indicator against the friction face whilst rotating the rotor. That will measure the amount of "elevation differences" along the rotor area. As you may know, not all runout is caused by deformed rotors, but also from improper bedding. I cannot remember at this moment what the suggested runout spec is, however my estimate would be somewhere around .002" to .0015" on a properly calibrated dial indicator. I'm not sure if Autozone or other stores still have a "tool loan" programme like they had before I emigrated from the US, but last I remembered they did have dial indicators.

Whilst some runout will exist, excessive will cause some "shimmy" or "shuddering", even in the manner that you describe it. This is one thing to definitely check if you haven't already.

If your runout is within spec, then you may want to re-address the caliper itself. Again, not all remans are terrible, however it's been well documented about many remans having caliper spread. This spread can indeed introduce a whole lot of problems, however the runout is cheaper, easier, and quicker to address first.

Foxxtron

iTrader: (1)

BTW, this is a pretty good instruction video: http://www.youtube.com/watch?v=H_1ySs7liS4

Again, since it's youtube, always perform at your own discretion.

SparkyJJO

iTrader: (11)

Thanks for the explanation and link. Yes autozone has a tool loan program (in fact I have one of their slide hammers right now for when I do my axle bearing once the new axle arrives).

For what it's worth, the old pads were evenly worn, just excessively worn on the driver side compared to the passenger side, and inboard pad was worn more than the outboard pad.

I had my ABS fuse pulled today. It seemed better, so I'll leave it pulled for a while and see how that goes. Not like ABS is that useful during the summer anyway. In the meantime I'll look into seeing if autozone or advance auto has a dial indicator rental.

Foxxtron

iTrader: (1)

Actually, I should also mention that the ABS module in my previous car also had a defect, however this wasn't easily detectible through any strange mechanical behaviours. I decided to check on it when the "abs inop", "ASR off", and "brake" instrumentation indicators would simultaneously light up. I did this with the OBD instrument (can't remember what it's formally called) from the Autozone tool rental, and discovered an error code related to the defect. Just throwing this out there as well.

AFA the pad wear is concerned, it is okay for the inner pad to be slightly more worn than the outer on the same caliper. This is due to the nature of sliding calipers, however if the "expected" pad wear differences between outer and inner on the same caliper are significantly different, then you may indeed have a problem with caliper (most likely slider pins).

Also, even if the pads appear to have "normally flat" wear, it's always a good idea to check your rotor's runout, because even if it does take some time, slightly excessive runout can introduce more headaches later on.

Major_Lee_Slow

iTrader: (1)

There was no mention of inspecting the rear brakes. Have you checked them out.

Also, nothing warps rotors faster than improper lug nut torque. Always tighen the lugnuts to 100 ft*lbs with a calibrated torque wrench.

SparkyJJO

iTrader: (11)

Rear brakes appear to be OK, no abnormal wear on anything, stuff moves freely, etc.. I'll be checking them again when I adjust my parking brake and replace my axle bearing.