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Brake question, Is this Normal?

M

Mstrkage

NAXJA Forum User
Location
Whiteman AFB, MO
I took my brakes apart for the first time yesterday while I was changing the u-joints in my axle shafts. I noticed that only about half of the piston inside the caliper is actually contacting the brake pad. I wonder if this is normal or not.
My heep is an 84 with the 2.8v6. The braking sucks, there is no single circumstance where I am actually able to lock up the brakes except on slick ice.
 
Maybe I am just not understanding the problem 100% but I am not sure how that is even possible unless your caliper piston has been worn down so bad that it has cocked a little bit inside the caliper itself. I would just get a new or reman caliper and be done with it.
 
Basically when the caliper is mounted onto the bracket half of the piston is above the pad the other half is actually making contact with the pad
 
no its normal. if i have it pictured in my head as your stating it. I believe what your trying to say is the piston is not completly flush with the pads. half the piston has contact and the other half if above the pad but it is still horizontal with the pads. if the piston looks tweaked it is not normal. replace asap.. also if one pad on one side is smaller than the other then replace. piston is going bad.. post pics for further refrence
 
Last edited:
As odd as it sounds, that's how it was designed. As stated above, the piston should be flush with the pad and able to move in a perpendicular plane, but only about 1/2-2/3 of the piston actually make direct contact with the pad backing plate.

I looked at mine when I first got it and was absolutely positive something was wrong, but after swapping every single part of the front axle from an '86 to an '88, there is no difference in pad to piston location with any combination of parts. It makes no sense to my feeble mind how this is a good design, but it's been that was for 200,000 miles on this axle, so I'll just chalk it up to way too many drugs back when I should have been listening in physics class.
 
So as long it's "normal" I won't worry about it. But I do concur that it doesn't make much since. The braking capabilities of my jeep are horrible right now so I guess I should start collecting parts for an upgrade.
 
I'd bleed them again and again 'til you think they're done and do it again... then make sure you've got the rears adjusted properly before I condemned them. Mine were the worst brakes I'd ever had (and that includes a ton of 4 wheel drum brake cars) until I got pissed and re-adjusted and serviced everything. Still not the best ever, but they'll stop better than most drum brake only cars....
 
I checked my fluid and yeah it's full but looks nearly black, so I guess I should change my fluid! Will that make a difference in how well I stop?
I'm going to start searching the threads to find a write up on a brake upgrade that I like
 
Mstrkage said:
I checked my fluid and yeah it's full but looks nearly black, so I guess I should change my fluid! Will that make a difference in how well I stop?
I'm going to start searching the threads to find a write up on a brake upgrade that I like
Click to expand...

absolutely-- brake fluid absorbs moisture and becomes less of a fluid coupling over time. Fresh fluid should help a bunch.
 
Especially with fluid that gunky, you could have a blocked passage in the master cylinder itself; causing reduced braking power. Changed the M. cylinder on my '01, difference was like night and day.
 
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