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Posted By: nikothenomad Interesting Brake Pad / Caliper Photos - September 27th 2018 9:11 pm
So a bit ago we had a brief caliper freeze up. No idea why... assumed it was all of the dust from the many dirt roads we had been cruising. We let it cool down and bled the brakes to release any air that may have been in them. After that no more problems. Kept an eye on them constantly and used our temp gun to keep checking them.

We are now in a place where we could look at them and this is what we found...

https://photos.app.goo.gl/fcb5kW5Mt14W9uog6

https://photos.app.goo.gl/86qdqrQPHF7nWRuy7
Posted By: CatFish Re: Interesting Brake Pad / Caliper Photos - September 28th 2018 1:48 am
The "silencer" pad/spacer behind the brake pad appears to have shifted or moved around. I'm not familiar with Dodges, but I've never seen that before. Might have happened after it overheated.
Posted By: nikothenomad Re: Interesting Brake Pad / Caliper Photos - September 28th 2018 3:18 am
Yes catfish since it heated up pretty good it appears the glue melted and released the spacer which then melted to the piston. I'll scrape it off tomorrow and see what we are dealing with. Test the piston and then look into a rebuild. Looks like we've got phenolic pistons which surprised me due to the age. Also I thought they didn't hold up as well to heavy duty driving and the kind off braking we have to do in mountainous territory but apparently they drugs for thirty years.
Posted By: wrcsixeight Re: Interesting Brake Pad / Caliper Photos - September 28th 2018 9:22 am
I have some HAwk HPS brake pads on the same calipers. The shims are actually riveted to the backing plate of the brake pad.

August 2017, before going on a 2500 mile eclipse roadtrip, I inspected the brakes and found the rivets had sheared off and the spacer was no longer adhered to the backing plate on Drivers side inner.

About 2/3 of the way through the roadtrip with lots of big elevation changes and brake usage I was getting brake noise in a straight line no braking that would go away when braking.

On my return I reinspected the brakes and found the friction material had begin separating from the backing plate.

I took good photos, sent them to Hawk, and Hawk sent me new pads under warranty. I do not believe the friction mterial started lifting off the backing place on one edge because of the shim, but all issues were on one of the 4 pads

I kept wondering why the backing plate sheared off the rivets.

The calipers can basically move 0.5mm or so forwards or backwards, and the shim basically needs to be able to slide on the piston that 0.5mm, meaning that the shim where it touches the piston should be lubed. If it is not lubed it cant slide, adn shears off.

Your shims had those little tangs, perhaps an adhesive too to hold them in place on the backing plate.

With no lube between the shim and piston they just work their way out of position as the caliper moves that 0.5mm inside the ways/ caliper retainers.

The HAwk HPS pads are easily the best brake pads I ahve ever employed in the last 17 years. I;ve never had so much confidence in braking ability. the fact the friction material was peeling off the backing plate was disappointing, but My brakes have worked perfectly since the warranty replcements have arrived, make no noise, ever, since I lubed the the shim and piston face.

Do not get long life brake pads, in my opinion, they have horrible friction, might beat the F out of the rotor, and might allow one to go way too long between inspections of themost important feature on any vehicle, the brakes.

The little rubber bands which come with the 7$ caliper hardware kit, stopped all brake rattle when i finally figured out how they are supposed to be installed, which is basically in between the caliper and the retainers to cushion them and keep them centered. Last time i used an innertube to cut my own rubber bands as they do get crushed and break.

I'd done many a pad slap in the past, but I was ignorant of the finesse required to get these brakes to work as well as they can.

The calipers need to move side to side in the ways, buttery smooth. the interior brake pad need any sharp corners filed off which might otherwise get stuck in the ways, the ways need to be smooth as a babys bottom and lubed and the rubber bands installed inbetween the lubed ways and the calipers. Anything less than this will still allow braking, but the pads can kink and wear improperly and cause brake drag, making everything worse.

I never thought about the lubing of the shims where they touch the piston but the pads have to move slightly within the caliper, and with no lube the pistons push the shims out of the way as the pads move within the caliper.
Posted By: CatFish Re: Interesting Brake Pad / Caliper Photos - September 28th 2018 1:11 pm
Originally Posted by wrcsixeight


Do not get long life brake pads, in my opinion,


My opinion as well, stay with the semi-metallic. Avoid the ceramic pads as they will cook/warp old van rotors and melt bearing lube no matter the make or model.
Posted By: nikothenomad Re: Interesting Brake Pad / Caliper Photos - September 28th 2018 3:09 pm
68 and catfish, agreed on the long life pads. brake pads are one thing i check regularly, anyhoo.

i am debating if the glue came off of the pad and that is what caused the stuck caliper or not? either way, even though they have not been locking up on us since that one time things were obviously not working as they should have been despite plenty good braking (considering the two crashes that happened 25 yards in front of us the other day on the highway which we needed to avoid - my confidence in the stopping ability despite what a mess the system is in was confirmed).

68 i know that you keep mentioning the 'ways' and my fsm even mentions something but i am still working to figure out what in the world i am looking for. i'll read and re-read your post and i'm sure i'll get it all figured out soon and when i put her all back together make sure those areas are lubed.

for now, my OEM 'like' idlers are due to come in today so that's exciting. sure hope they slide in with just enough resistance to make me feel confident they will fit nicely and not permit play.

meanwhile, i removed the shim from the piston and gave it a quick clean. other than a 'visual' imprint it didn't leave any material on the piston. still not so sure the piston shouldn't be replaced? we ran a quick test with a few pushes of the brake pedal and the piston does exit the cylinder as expected. not sure about retraction because we had it off of the rotor so i guess with no pressure on it the piston will stay out until i put it back in.

https://photos.app.goo.gl/xUDAwWt6RPeUoDij6

https://photos.app.goo.gl/og5E4puD1T1mPhqs6


i was surprised to realize that our pistons appear to be phenolic. given that i had been reading about the differences i would not have thought on a van that they would have used those over metal back in the day. i thought that the braking and such that we do in the mountains and also the load that vans typically have not to mention ones converted like ours would have been fitted with metal. so, that was a lesson learned. but... they did last 30 years and seem to still be working although i may do a rebuild anyway since i've got it all off.

also finally addressing the control arm bushings. while they are not completely gone we decided that we'd go ahead and do them because they are the only thing bushing wise in the front end that has not been done and is still original. figured at that point we would at least be in a better position not having to assume that old control arm bushings are the root of all other evils that happen the the new stuff we keep putting in up there.

well, guess the rain has stopped so i'd better stop my fingers.
Posted By: nikothenomad Re: Interesting Brake Pad / Caliper Photos - September 28th 2018 9:11 pm
And.... in my opinion... the verdict is.... the shims on the pads disconnecting caused the original caliper lock up!

These are photos of the driver's side (which has never had a lock up or overheat problem)... Just look at that shim slide!

https://photos.app.goo.gl/djt8cc4iiYNDWE1f8
Posted By: LazySteve Re: Interesting Brake Pad / Caliper Photos - November 12th 2018 10:46 am
I would recommend you swap the pistons for stainless steel while you are in there.

My '73 still had phenolic pistons in when I got it and the driver's side would seize up (even after I carefully cleaned up the piston and bore and re-installed). I put stainless pistons in and it has been fine even driving through mountains in Spain and France.

The phenolic piston was fitted on some heavier vehicles, ironically it is supposed to allow the system to cope with more heat than metal - the idea is to prevent the heat from the pad from getting straight to the fluid, obviously if the piston sticks the pad is going to get way hot either way.

It's not an "old tech" issue either, the WJ Grand Cherokee jeeps have phenolic pistons in the back end and they are notorious for sticking on.
Posted By: nikothenomad Re: Interesting Brake Pad / Caliper Photos - November 13th 2018 1:56 pm
thanks, steve. we've tested the caliper / piston and all is working as expected. so, for now we plan to replace the brake pads with wagner 'all in one' pads to avoid the issue we had this time around. the phenolic pistons have been performing brilliantly for us up until this point and we are convinced (at least at this juncture) that the adhesive issue on these new pads is the reason.
Posted By: LazySteve Re: Interesting Brake Pad / Caliper Photos - November 17th 2018 9:38 am
Makes sense if it started with the pads. We'll find out for sure when it all gets hot.
Posted By: nikothenomad Re: Interesting Brake Pad / Caliper Photos - November 17th 2018 3:07 pm
Well.... we will definitely find out now that we have swapped to pads that have an integrated 'non-glued' shim. IF there is a caliper problem it will not be a result of the shims slipping again as these have none to slip.
Posted By: nikothenomad Re: Interesting Brake Pad / Caliper Photos - November 09th 2019 2:05 pm
Update... Wow, can't believe it has been a year since we checked original calipers / pistons and changed to an integrated non-glued shim pad. In that time we have put a few miles on her 10,000 which is a lot for us in a year. We've also had her out in CO and climbed and descended many 12,000 footers with some pretty good grade changes Knock on wood... no problems at all! Still running original calipers / pistons and really appreciate the new pads they grip and stop better than any we've tried before.

Conclusion.... Previous pads were duds with glue on shims failing and in one case causing piston to freeze up.
Posted By: frscke1 Re: Interesting Brake Pad / Caliper Photos - November 10th 2019 6:22 am
So what brand are these new pads ….
Posted By: nikothenomad Re: Interesting Brake Pad / Caliper Photos - November 10th 2019 11:38 pm
frscke.... HA HA I knew someone would ask! Can't for the life of me remember... Think they were Wagners. I'll have to check my docs which are in the van next time I go down to say hello to her. She's been sorely neglected this last month as we are taking care of my pops. Did go down to start her this morning though and after filling the float bowl she turned right over - not bad for a whole month of sitting alone in the parking lot.
Posted By: Astrocreep66 Re: Interesting Brake Pad / Caliper Photos - November 12th 2019 12:32 pm
Look like Wagner thermo quiet.
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