Slider bolt problems

[ProwlerGT]

Originally Posted by tabasco122

Just a suggestion, lol. Since nobody else is helping you and i dont know much about brakes, i figured i would try to make you laugh...

You succeeded.

[ProwlerGT]

Thanks to all!

Darksurfr - Yeah, I guess I didn't have the entire thing "caked" like you say. I'll try that and I was thinking about lubing the bore first with a "straw" cause whats happening is the rubber bushing (or grommet as it was called) is acting like a plunger. The green stuff is the new permatex caliper guide lube I bought just to do this job.

sweet91, htlaets1 - I have lithium spray grease and as I've already screwed this up royally the first time I think I'll stick with the caliper lube since I have it already though I am curious now as to knowing which one works better; the appropriate lube or the lithium grease?!??!

I just thought that once all this was over that the bolts should slide in and out of the bore of the bracket pretty easily with minimal "hand" effort.

[ProwlerGT]

Well I guess this was a lil bit of a false alarm. I lubed the bore with a straw all around it inside and then lubed the bolt/bushing well and it slides in and out of that thang very nicely now.

Just cause I could never get an answer from anyone (even on 2 other sites) I'm confirming that there is an air vacuum (or I should say "fullness") type effect created when the slider bolts go in the bores. As they (or at least just the top most bolt - the guide bolt with the bushing on it's end) screw inward into their threads on the caliper the force of air behind the bolt in the bore of the caliper bracket pushes back on the bolt. I know this because as I was threading it back inward I encountered resistance ("fullness") from the air behind it which actually pushes my hand in the outward direction. THIS IS WHERE THE SPREADING EFFECT HAPPENS WHEN YOU RELEASE THE BRAKE PEDAL! I never knew this till now.

So you have the pistons retracting into the caliper for 1 by the suction/vacuum effect created in the brake lines/reservoir after the brake pedal is released and 2 the slider bolts pushing the caliper back apart again so that the pads do not stay stuck to the discs causing overheat and loss of braking power/distance.

I put caliper glide/slider lube at the edges of the dust boots that surround the slider bolts as well to prevent water/debris entry into the bolt bore's over time.

[ProwlerGT]

Perhaps I spoke too soon, but I have everything reassembled now and now the damn rotor/axle will not turn at all. I'm trying to turn it with my hand only with the tire off and it will not turn. When I loosen the slider bolts I can turn it somewhat, but when they are in their fully tightened position I cannot turn it at all. My only hope is that once I put the wheel on it'll spin cause I noticed the rotor/disc is not sitting quite straight on the hub/studs and sure I know it has to be exactly right, but even if the wheel straightens it out it seems like the slider bolts are crunching the pads down onto the rotor.

[ProwlerGT]

Well, I see what the problem is now. When I put the new slider boots, bolts, and caliper all back together on the car the Lock bolt (not the guide bolt at bottom; both bolts are the slider bolts) is for some reason not going in all the way leaving the caliper sitting lop sided. If I look down from the top of the caliper groove along the disc I can see the disc actually touching the caliper itself and not the pads. I have the pistons retracted all the way in so I know that isn't it.

I don't know what else to do, but to remove it all again and this time not fasten/secure/clip the slider rubber boots into place until the caliper seems to have set right. Its as if air is trapped behind the lock bolt and it cannot get out.

[ProwlerGT]

THIS IS THE STORY OF LIFE: TOO LITTLE, NOT GOOD ENOUGH. TOO MUCH, CAUSES PROBLEMS. BALANCE IS A HEALTHY LIFE REQUIREMENT IN EVERY WAY BECAUSE IT BRINGS WHAT IS NECESSARY TO MOVE FORWARD.

HA HAAAA ALL THAT PHILOSOPHY FROM DOING A BRAKE CALIPER! NOT THAT ANYONE IS REALLY WATCHING ANYWAY. LOL

I have TRULY found the solution this time. After multiple removals of the caliper setup from the bracket the issue was TOO MUCH SLIDER BOLT GREASE. I went to Advance Auto before all this and bought 2 packages that included 2 packs in each of .25 fl oz of slider lubricant (Permatex). There are no specific instructions on the package except to lube it and looking this up on this site as well as the internet didn't get me anywhere. I guess this is supposed to be one of those common things that is just "KNOWN" that not everyone really knows.

I found that I had a packet of slider lube from Autozone and IT HAS DIRECTIONS which gives us a sense of HOW MUCH of this lubricant is supposed to be used per bolt.

Autozone packet instructions: "Apply light coat to back side of pad to permanently absorb vibration squeal noise." - thats not related to this thread, but its good to note that. Continued: "Lubricate caliper slide and all moving parts. Contains enough product for one axle."

That last part is very KEY..... VEEERY important. This packet is only .14 oz in volume which means that only a SMIDGEN (divide by 4 bolts for 1 axle) of it should be applied per bolt (3.5 oz per bolt). I'm not suggesting you measure this out, but just try to evenly distribute the lube on the bolts with just enough to "coat" them leaving a transparent film of lube. The permatex packet (based on the Autozone packet directions) contains enough glide lube for both axles or all wheels. I had bought 2 packages of 2 packets each cause I thought initially that I had to cake this grease all over the place per caliper based on what someone on here or some other site told me which turns out to be false.

You see cause not only should the space inside the caliper bolt bores & rubber slider boots be lubed, but it must also be "air tight" such to not allow contamination in the bores which will eventually lock up your brakes. This air tight area is what will spread your caliper apart again off the pads after the brake pedal is released. If you cannot squeeze the caliper together FIRMLY with your bare hands (assuming the pistons are backed all the way in already) and watch it spread back apart on its own afterwards then your caliper setup is not what is could/should be. Since we know the pads are "floating" in the caliper and nothing actually grabs them and pulls them off the disc the action of the caliper spreading back apart again must allow the disc to "ever so slightly" push the pads far enough back (perhaps 1mm or less) to not scrap and heat up the disc.

TIP: If your caliper is lopsided you have too much grease in the slider bolt bores.

TIP: If you pull your lock or guide bolts out all the way (carefully) and there is grease CAKED and covering the END of the bolt like a tiny little CAKE sitting there that amount represents the excess grease that should be removed. You may have to repeatedly screw the bolts ALL the way in the caliper and squeeze the caliper together (without the pads on) AS FAR AS YOU CAN till the rubber boots are almost fully compressed and remove the bolts again until you no longer see this little CAKE at the end of the bolt to know that you have the right amount of grease in there UNLESS you are WONDERFUL enough to do it right the 1st time.

TIP: The distance between the caliper bracket surface (where the rubber bolt boot connects) and the caliper thread hole surface should MATCH for BOTH Lock and Guide slider bolts. If they don't match then the one that is of greater length is the one with too much grease.

TIP: Your caliper assembly is setup properly when you can squeeze it with your hands (granted pistons retracted all the way) and it spreads back apart on its own.

TIP: To get excess lube out of the caliper bracket bores use a simple STRAW. Its clean and won't scratch up the inside of the bores which could be bad news later. Just push it is dead center and when you get it at the bottom of the bore pull back about 1/4" and angle it and push to the bottom. Do that again and again going around the bore bottom and pull the straw out dead center and you'll have collected the excess grease. Put it all back together minus the pads and squeeze the caliper together by hand till the rubber bolt boots are fully compressed. If you can't get them fully compressed do the straw thing again. Its a pain in the ass, but once you get this right your caliper will love and kiss you for fingering it so much.


I'm going to do a write up on this soon cause I think it would help people. I never realized just how delicate setting up a caliper can be till now.

[SUPERTOM]

my rear brakes are sticking. all of this info is very helpful.
I just orded a used set of calipers on ebay and plan to rebuild them and use my current ones in the process.

[ProwlerGT]

Originally Posted by SUPERTOM

my rear brakes are sticking. all of this info is very helpful.
I just orded a used set of calipers on ebay and plan to rebuild them and use my current ones in the process.

Rebuilding rears may not be that bad, but I became extremely aggravated with how careful I had to be with the right tools not to scratch, right fluids to lube, right cleaning technique, etc... while I was trying to rebuild my front calipers. In the end I gave up and bought all new calipers and I don't usually give up easily at all. It was just taking too many hours.

I would strongly suggest a fill, dip, and soak technique overnight in some dissolving solution and remove all rubber from the calipers and caliper brackets. Let it all sit submerged in the solution overnight. Cleaning these things out manually is a real bitch and I for one don't like having that brake parts cleaner or electronic parts cleaner or engine degreaser cleaner stuff on my hands at all for any duration.

I guess now that I'm thinking about this it would be easier than I had tried before scrubbing everything with my hands.

Caliper brackets - I suppose the best solution is to do what I recently figured out. Set the caliper brackets on a rag or somewhere fairly clean and have the slider bolt bores facing up. Fill the bores with brake parts cleaner to their tops and let it soak for a while. Once you pour it out it should dry fast (make sure its completely dry before reinserting bolts or new grease). I would probably use a round rounded plastic bristle brush on the inside bores before pouring out the cleaner too to ensure all old gunk pours out of the bores.

For the pistons (which will be caked on the sides with gunk) you will need to remove them with compressed air (watch your hands; put a rag and small piece of wood in front of the piston face cause it will FLY OUT). Do not use more than like 15-20psi... maybe just 10 psi. It will come out fast. If I was doing this again I'd find a small container to fill to soak the pistons in - otherwise just cake them several times with brake parts cleaner till the gunk comes off the sides of them.

For the caliper I'd plug the brake line hole with something and flip the caliper over and fill it up with as much brake parts cleaner as I can. I know this is gonna sound funny, but to not waste all your brake parts cleaner perhaps you could get some marbles or a ball bearing or two and put them inside the caliper to occupy space so that when you spray in the brake parts cleaner it'll fill all the way up along all the piston walls/bores while saving you some of the cleaner.

WOW. Maybe if I'd thought of doing things this way originally I wouldn't have had so much trouble rebuilding my front calipers the first time! lol - I would've much rathered keep my stock calipers too cause the reman's I got all have mismatched bleeder valve sizes and I can't use my speed bleeders on one of them cause it just won't thread in as easy as it should and I don't wanna ruin the threads in the caliper.

Personally for the caliper bracket bores I used electronic parts cleaner because it dries much faster and much drier. As long as all debris is removed from whatever it is you are cleaning and you lube it with the proper stuff afterwards using electronic parts cleaner didn't seem to hurt anything.

Oh I just remembered why it was such a pain to clean my old calipers. lol - I wanted to paint them and unless you plan to soak the entire caliper assembly painting old calipers is NOT a good plan unless you have a big dip'n-soak tub with some heavy duty stripping cleaner solution.

[SUPERTOM]

I got my used set and started messing with them. The rears when you pull them out they slide back in on their own. But on the front ones if you slide them out they dont slide back in on their own you have to manually do it. So are my fronts bad?? How are they supposed to work? Ive searched all over this board and cant find a damn thing.

Oh yeah and im talking about the slider bolts not the pistons

[ProwlerGT]

Originally Posted by SUPERTOM

I got my used set and started messing with them. The rears when you pull them out they slide back in on their own. But on the front ones if you slide them out they dont slide back in on their own you have to manually do it. So are my fronts bad?? How are they supposed to work? Ive searched all over this board and cant find a damn thing.

Oh yeah and im talking about the slider bolts not the pistons

Did you thoroughly clean out the bores of all the caliper brackets before reassembly and before regreasing?

After you clamp the caliper together with your hand (1 hand or thumbs on the caliper bracket while pulling towards you with your hand on the actual caliper with the pistons in it) as it is ON its slider bolts and caliper bracket the caliper should squeeze the caliper rubber slider bolt boots together nearly as far as they can squeeze/compress. After letting go the caliper should then spread back out on its own (not inward towards the bottom of the caliper bracket bores, but AWAY) away from you towards the wheel well. This should be the same for all 4 brakes I do believe. If they don't spread back out (pistons compressed all the way into the caliper FIRST) towards the wheel well then there's a good chance the caliper is sitting slanted and the rotor is touching the caliper and/or caliper bracket metal which is NO GOOD.

When "setting up the caliper" (rear or front) they should be in a position where the slider bolts are almost (maybe 80-90%) all the way into the bolt bores with just LITTLE enough grease to allow them to slide and go all the way in too.

*NOTE: Rebuilt rears may act differently due to the cap of one of the bores not being air-tight since remanufacturing. I've taken to the idea of RTV'ing all around that cap (cleaning it first) so that its air tight and debris can't get in.

So in short: You are sandwich clamping the caliper with your hands and it should move backward from you towards the wheel well maybe .5 - 1 inch worth of distance. If it doesn't then you may need to remove some slider bolt grease and/or reclean the bracket bores for the slider bolts.