Evening out double piston calipers

[Cubey]

Back when I did my brake pads, I didn't think and I used a clamp on a single piston, making them uneven. Then I tried to fix it by using an old pad, like you should. But, I guess I didn't do a good job.

When I was changing the shocks the other day, I found the RH caliper dragging a bit and the outer pad is unevenly worn.

I was lazy the other day and didn't take it all apart, but tried clamping it near the piston sticking out extra by not removing the reservoir cap, figuring the pressure would even out to the other piston. Well, the piston went in a tiny bit and the drag went away. I haven't drive any, so I don't know if it's still uneven or not. Really it needs new pads now due to the uneven wear, but they still have enough pad that I could put it off a year if needed.

The inner pad at the pistons side looks evenly worn, oddly enough.

How do you go about fixing the caliper? You'd think it would equalize under pressure, but I guess not. Maybe the other piston is sticking? Or just not evened out properly? Is there really anything I can do now without replacing the pads? I'm guessing the uneven pads will force it to be uneven now, no matter what I do to it. Warped rotor caused it maybe?

 

[Double-S-Diesel]

outer pad worte uneven is usually the sliders hanging up

 

[Cubey]

outer pad worte uneven is usually the sliders hanging up

Hmm, I thought I greased everything up good. There's really no sliders (as such) on these calipers. The pads just move around the caliper on built-in slide areas.

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[Cubey]

Here you go, a good pic I took last March when I changed the pads. You can see the slide surface for the inner pad up top on the right.

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[Cubey]

And a caliper stock photo. The area immediately next to the piston's sides is the slide area. You just grease it up and that's it. Nothing should be sticking.

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[chillman88]

I believe he's referring to the caliper slides, as in the caliper might be hanging up and not fully releasing. Caliper slides would be the pins that hold the caliper in on the sides, those metal clad rubber pieces.

I'm thinking it might just be time for calipers. How did the seals look? I know they dry up with age and gunk gets in there and they start sticking. They can be rebuilt when that happens but up here in the rust belt it's not as cost effective to fight with them.

 

[Cubey]

I believe he's referring to the caliper slides, as in the caliper might be hanging up and not fully releasing. Caliper slides would be the pins that hold the caliper in on the sides, those metal clad rubber pieces.

I'm thinking it might just be time for calipers. How did the seals look? I know they dry up with age and gunk gets in there and they start sticking. They can be rebuilt when that happens but up here in the rust belt it's not as cost effective to fight with them.

My E350 lacks those metal+rubber pins. (My F250 has 'em)

Instead, it just uses metal to metal on top (knuckle to caliper), and a "key" and spring on the bottom. I remember greasing them up but maybe I didn't put enough, or it got washed away somehow.

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Looking in my F-series Haynes manual, it mentions them as heavy duty "early model key retainer type", so trucks had them too at one point. I replaced the keys and springs because one spring was broken when I went to do the brake pads.

All of these illustrations apply to my E350. The photo is the metal-to-metal contact up top, and the key/spring are in the bottom two drawings.

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I guess I will pull the caliper off and have a good look. Maybe something is wrong down there with the key/spring since that's what keeps keeps the caliper attached basically, and keeps it from rattling up and down. There is one retainer bolt on the bottom too, hence the two rounded cut-outs in the keys, so you can install them on either side and it allows the one bolt to be installed.

It got new calipers last year when I had that $1000+ work on the thing done right after I bought it, because I didn't see and the guy didn't disclose trans fluid in the brake system. I had to have it fixed, I couldn't drive it 300 miles back like it was.

 

[Cubey]

This might illustrate better. The metal-to-metal place is the "v grooves" the Haynes manual mentions that you need to grease. And yes, I greased it.

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[IDIBRONCO]

so trucks had them too at one point.

All of my Half tons, including my 1986 Bronco (stock), had them. I've had several dent sides and my 1981 F150. The only one that I can't remember for sure is the 1975 F250 that I used to have. I didn't have it long enough to have to do brake work on it. I do have to admit that it was in good enough shape that if I still had it, it would have an IDI swap done to it. It only had one tank so no FSV to mess with!

 

[Cubey]

All of my Half tons, including my 1986 Bronco (stock), had them. I've had several dent sides and my 1981 F150. The only one that I can't remember for sure is the 1975 F250 that I used to have. I didn't have it long enough to have to do brake work on it. I do have to admit that it was in good enough shape that if I still had it, it would have an IDI swap done to it. It only had one tank so no FSV to mess with!

Interesting, since it's considered heavy duty. It's on a 1 ton dually, in my case! But maybe the same design (scaled down?) was used on lighter duty trucks too.

 

[dgr]

Since there appears to be no replaceable wear part there, I would check for a worn spot where they slide together- a small lip it could catch on. One side has all the work trying to slide while you're applying the weight of the van against it with the pedal.

Stomping on the pedal (don't actually stomp it until you have pressure) would even the pistons out after a brake job unless a piston is sticking.

 

[IDIBRONCO]

Interesting, since it's considered heavy duty. It's on a 1 ton dually, in my case! But maybe the same design (scaled down?) was used on lighter duty trucks too.

I don't know about heavy duty. I was told that they used the same thing on cars, but I have no experience there. I'm not sure how it could be scaled down either unless the pieces are shorter in length. It does seem like I've seen this setup on the front of an IDI powered van too.

 

[hce]

That style caliper still slides in the bracket. My 84 has this style. It appears everything is asselmbed correctly. with caliper off check that the key slides smoothly on the caliper. Step 2 remove the pads and leaf spring, and install the caliper and see how it moves with just the key, should move easily. Step 3 install the key with spring and see if a caliper will move with a nudge of a soft hammer or use a block of wood. Might have to file down the surfaces on the v groove to add clearance, new caliper may be too tight. Make sure to check the full range of motion of the caliper in the bracket. The spring key taps in with a hammer, no hard force. Also grease, antisieze all sliding surfaces between caliper, spring, key and bracket.

 

[Black dawg]

These calipers are notorious for uneven wear, and also feeling like they are dragging.

make sure the pads fit the caliper correctly, and caliper can slide free.

 

[Cubey]

These calipers are notorious for uneven wear, and also feeling like they are dragging.

make sure the pads fit the caliper correctly, and caliper can slide free.

Will do. The LH side is fine, no uneven wear and no dragging. I just need to wait until Thursday when the weather is clear.