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Brakes jolting


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While I was working on the front end of my truck the other day I noticed that the passenger side bads and rotor were completely worn through. So I got a new rotor for the pass side and new pads for both sides. I put it back together and pedal pressure and stopping power all seem fine.

 

Then the next day when I was braking kind of hard while coming to a complete stop they kind of jolted. Still stopped fine, but there was a bit of a bump just once. I tried to get it to happen again and it did not repeat itself so I thought perhaps something wasn't seated right and it was popping into place. But while I was coming to a stop in the parking lot of work this morning the same thing happened again. It only seems to happen when braking a bit hard and completely stopping.

 

I am not hugely concerned about it be because I haven't had any problems stopping, but it is still sort of offputting. I had never done any brake work on a Jeep before and the caliper bolts were different than I was used to (I have only owned japenese automobiles before the manche). When they come through are they supposed to push directly on the pad? I only put them on sort of tight because I didn't think they should be pushing the pad onto the rotor, but now I am thinking I did something wrong.

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I had never done any brake work on a Jeep before and the caliper bolts were different than I was used to (I have only owned japenese automobiles before the manche). When they come through are they supposed to push directly on the pad? I only put them on sort of tight because I didn't think they should be pushing the pad onto the rotor, but now I am thinking I did something wrong.

Man, I'm confused. Are you asking if the caliper mounting bolts should push on the pads? Hell, no! The mounting bolts go through sleeves and should allow the calipers to slide sideways. The only thing pushing on the pads should be the caliper pistons.

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I had never done any brake work on a Jeep before and the caliper bolts were different than I was used to (I have only owned japenese automobiles before the manche). When they come through are they supposed to push directly on the pad? I only put them on sort of tight because I didn't think they should be pushing the pad onto the rotor, but now I am thinking I did something wrong.

Man, I'm confused. Are you asking if the caliper mounting bolts should push on the pads? Hell, no! The mounting bolts go through sleeves and should allow the calipers to slide sideways. The only thing pushing on the pads should be the caliper pistons.

Thats why I backed them out a bit, but they were still pretty close to that pad.

..

 

if you have normal bolts on the caliper, you need to go buy the correct ones. the correct ones allow the caliper to slide (they should be greased when installed), and they bottom out far before hitting the pad

Yeah, they didn't bottom out till they hit the pad. But the threads looked fine and they had that long polished sleeve on them so I think they are the correct ones. Allen head right?
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What year is your truck? And what year rotor did you get? Did the bolt bottom out on both sides, or only the side with the new rotor?

 

Jeep changed the hubs and rotors between 89 and 91. I think '90 was the first year of the "new" design, but I don't remember exactly. If you got the wrong rotor, it has a slightlky different offset and won't work with your original hub and knuckle and caliper.

 

See if your new rotor looks the same and has the same thickness at the "hat" section that fits over the hub.

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While doing my fronts I noticed it looked like the rotors were one piece with the hub...

I may be wrong, but I don't think I can just slide the rotor off like what I'm use too. But I put a micrometer on them and they are with-in spec. so I just left them...

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It's an 87. It looked the same, but I guess I didn't know to look for that. I will pull the wheels off tomorrow and make sure the rotors are the same, because the drivers side wasn't replaced. But if that was the case wouldn't the caliper had trouble fitting on the wrong rotor?

 

After driving it quite a bit today, I did not experience the jolting though, so perhaps it has gone away. I am still gonna pull the wheels off and make sure everything is cool though.

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While doing my fronts I noticed it looked like the rotors were one piece with the hub...

I may be wrong, but I don't think I can just slide the rotor off like what I'm use too. But I put a micrometer on them and they are with-in spec. so I just left them...

 

I am guessing your is a 2wd. 4wds have a tophat style rotor and unit bearings. Early 2wds used packable bearing in a hub/rotor combo.

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While doing my fronts I noticed it looked like the rotors were one piece with the hub...

I may be wrong, but I don't think I can just slide the rotor off like what I'm use too. But I put a micrometer on them and they are with-in spec. so I just left them...

 

I am guessing your is a 2wd. 4wds have a tophat style rotor and unit bearings. Early 2wds used packable bearing in a hub/rotor combo.

 

Yelp,,, guess that clears that one up!! :D

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sounds like you have other fish to fry but from your original post i'll tell you this...

 

a random pulsing from your brakes could be the rear drums catching if theyre badly worn, mine used to do this under heavy braking it would stop pitifully then every once in a while they would actually catch and it stopped GOOD all the sudden and felt like it shuold but i hadn't changed pressure on the pedal.

 

i'm assuming the rears were so toasted (they were VERY toasted) that only heavy braking would move them enough to catch. (adjusters were also installed backwards the last time someone did them? DOH! (wasn't me))

 

so i'd pull a drum off and check that over

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It's an 87. It looked the same, but I guess I didn't know to look for that. I will pull the wheels off tomorrow and make sure the rotors are the same, because the drivers side wasn't replaced. But if that was the case wouldn't the caliper had trouble fitting on the wrong rotor?

 

After driving it quite a bit today, I did not experience the jolting though, so perhaps it has gone away. I am still gonna pull the wheels off and make sure everything is cool though.

If you had to back off on the caliper mounting bolts so they're not seated all the way, then everything is definitely NOT cool.

 

I was thinking about your problem on my way to church this morning. I assume you bought the truck used. Suppose the previous owner had put the wrong rotors or the wrong calipers on? That could explain why your pads and rotors were so trashed.

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Here is some pictures of what it looks like when the bolts are tightened down and the slide part of the pins are as far in as it goes.

Top:

Bottom:

 

It is an AMC number 103707 caliper, I am going to try googling that to see if it is the right caliper.

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