calipers stick from non use

[Dennis Texas]

Well seems like every time I get one of these cars out of storage even though they been in a garage the calipers stick (they are rebuilt). Sometimes I've just pulled the rubber seal back and sprayed p-oil in the seal, then take small welding pliers and force the caliper into the housing after a few times it works. Anyone have a easier solution?

[hrcollinsjr]

First of all p-oil (penetrating oil) is not the thing to spray around the seals. The best ideal that I can come with is that when you park it maybe you need to compress the pistons once it is parked, park in a climate controlled garage, or move to a less humid environment. How long are you leaving it parked? There are special brake friendly lubes you can use on the pistons and I believe they may also be rust inhibitors. Are the dust seals in good shape and in place?

Harold

[american opel]

pb blaster and other typs of penetrating oil helps to break free rusted bolts but after a short time they actually promote rust.one of the best things i have found is to put some anti-sieze on the bolts slides and rubber boot.this stuff never goes away!!!!i did a brake job on my wifes car"4 years later"and it was still there.60,000 miles later.

[Dennis Texas]

Car suspension to include brakes were all rebuilt and working when parked. The dust seal are still like new. They retracted as they should when initially parked, I been rolling it around the garage by hand when needed. When I got it out I was just going to take it for little spin to check brakes before taking it out on highway the front wheels lock down and don't release even when I open the bleed port they don't retract much, still very hard to turn wheel but not locked down as it is when I just step on the brakes. I't's like the piston seals stick. I have had this trouble on some other Gt's I had stored and after removing the calipers and spraying some p-oil inside the space between piston and dust seal and working it it would finally be operational. Its just work to have to do all that and I'll do it but I was just wondering if anyone had an easier way (maybe tap a wedge between rotor and pads but hate to take chance on messing pads up because I was too lazy to remove calipers). I checked the previous threads but those were mostly problem systems. Once they get freed up they work fine or they have in past this one I have not done before this one has sat about 5 years even the new rubber hoses had to be replaced because they swelled up and pinched off. I rebuilt the master cylinder also just in case, peddle is rock hard, only movement is the little fluid displaced for the drum brakes on the back 1/4 or maybe more on peddle. Garage is not climate controlled it's 7 car garage I would sell the cars first before footing that bill. I guess long story short do I need to just pack the space with grease between seal and piston or use hyd oil instead of hyd fluid to prevent this once I get them freed up.

[Dennis Texas]

Originally Posted by american opel put some anti-sieze on the bolts slides and rubber boot.this stuff never goes away!!!!i did a brake job on my wifes car"4 years later"and it was still there.60,000 miles later.

Anti-seize, any special type, I have some nickle out in garage I know it works great on header bolts and flanges I don't put those together with out it, just don't know about rubber based applications actually just never thougth about it. I can do that just put in between the dust seal and piston then?

[american opel]

i was going to tell you to replace your hoses up front but you siad you did this?the seals cant hold the piston in,they are there to keep water and dirt out.the only thing else that i can think off is your break fluid is old.break fluid should be changed every 3 to 4 years.water in your break fluid will rust the piston to the calliper.after driving car you wont notise a prob. because the heat and movement cleans it up.

[namba209]

Bad plam all the way around unless you carry a fire extinguisher in the car. Almost all lubircants/penetrating oil contain a fluid hydrocarbon in their recipe. Get the brakes hot, as in normal braking action, and the petroleum based lubes will burn. Not too good for rubber seals, that will melt and then the brake fluid will burn too. Best bet is to keep the whole area spiffy clean. Do not use brake fluid as a penetrant to free up the pistons, it's like a sponge to water, compounding your problem.

[american opel]

anti sieze of any kind should work,but now that im thinking about it dont put any on the piston behind the dust seal.i usually put it on the outside of the seal and piston.i dont know why but i dont think you should put any behind seal.

[hrcollinsjr]

I know you haven't mentioned the rear brakes but semi-metallic shoes are bad to stick to the drums if the e-brake is left on for an extended period of time. Once you break them loose they are usually okay.

Harold

[american opel]

Originally Posted by namba209 Bad plam all the way around unless you carry a fire extinguisher in the car. Almost all lubircants/penetrating oil contain a fluid hydrocarbon in their recipe. Get the brakes hot, as in normal braking action, and the petroleum based lubes will burn. Not too good for rubber seals, that will melt and then the brake fluid will burn too. Best bet is to keep the whole area spiffy clean. Do not use brake fluid as a penetrant to free up the pistons, it's like a sponge to water, compounding your problem.

i know the brakes get hot but they will never get hot enough to light ony kind of oil res.if they did the grease in the bearrings and the rubber seals would melt on every car made.

[namba209]

Originally Posted by american opel i know the brakes get hot but they will never get hot enough to light ony kind of oil res.if they did the grease in the bearrings and the rubber seals would melt on every car made.

Don't count on it. There's a lot of cooling air going around the rotors, but the latent heat build up from brake applications will cause any petroleum based oil to burn if it gets on the rotors and your brkaes will go south too..

[yellaopelgt]

My car has sat for years at a time....Mothballs, and lots of mouse-traps to see if varmits are present in storage.I move it a few feet every month,(so I dont get flat spots on the tires) pull and release the e-brake a few times, pump the brakes, engage the clutch, roll the headlights over, etc. Just to keep things lubricated. Also,NEVER leave a battery in the car....I've never had a problem in the 15 years I've owned this car(other than the normal 40 year old part replacement). I also lube all the cables, and do alot of preventative maintenance every summer,IE change all the fluids every other year or so regardless if its been run or not. So I'm sure that helps alot.Time is a cars worst enemy if you dont properly store it.

[opelbits]

Seized/sticking brakes are one of the most common problems with 'hobby cars'. The very simple reason is that regular use keeps corrosion from building up enough to be a problem.

But think about this...when cars are new, virtually all the parts on it had some kind of coating, whether it's a plating, paint, or anodizing. Most common replacement parts do not have a coating since most of them are stripped in the rebuilding process. The cheaper the rebuilt part, the more likely there is no protective coating. How many of you have used replacement master cylinders/calipers/water pumps/etc. that were just bare cast iron?
So when the caliper gets rebuilt, no one recoats the piston. It's a simple thing to do. After putting the piston back into the caliper bore, push it all the way in. Now back it out just a hair 1/32" or the thickness of a matchbook cover. Now paint the exposed area with an epoxy paint. This will protect the piston lip so it doesn't start corroding. The rust will work it's way past the seal to the inside and either makes the piston stick, or the now rough surface chews up the seal.

As for moisture in the fluid, the only way to prevent that problem is to change out the fluid regularly or before long storage.

Neither of these are surefire guarantees, but lack of use and cheap replacement parts is almost certainly going to cause a problem.

[Dennis Texas]

Originally Posted by hrcollinsjr I know you haven't mentioned the rear brakes but semi-metallic shoes are bad to stick to the drums if the e-brake is left on for an extended period of time. Once you break them loose they are usually okay. Harold

Back brakes are really not an issue usually just drive a bit and pull handle on e-brake to stop it a few times and that cleans off any residue on shoes or build up on drum. I really believe it is not an piston corrosion problem on the calipers so I don't think painting it will be of much help. I'm just going to have to bust them down and free up the seals by exercising them back and forth. I'm kind of liking the anti-seize idea and may just wipe a thin coating around the area between dust seals and piston when I push them back into the housing inside the caliper housing where the piston slids that is exposed. A little of that stuff goes a long way and it stays put. I never store cars with batteries in them. Dead batteries and brakes are usually the biggest problems I have had from storage, battery is the easiest to eliminate just remove, some of these have been stored over 15 years now. I'm pulling them out along with all the other toys and will probably be selling them all off and looking into new projects. Thanks everyone for the input.

[oldopelguy]

I'm not sure anti-seize is the right answer either. The calipers in the Opel rely on the seal sticking to both the piston and the bore and deflecting slightly when the brakes are applied. When the brakes are released the deflection relaxing is what pulls the pads off the rotors to keep them from dragging. If the cylinder were lubed up so the seal didn't stick to it I'm not sure the calipers would release properly.

Hardest thing you can do to a machine is not use it. Easiest answer would be to drive it more.

[rjgilge]

Have a 70 GT, that the front calipers are not releasing...completely rebuilt, seals, pistons etc...new master cylinder, cant seem to get them to work right...bled system several times....pedal seems right not hard...both front calipers are both sticking and wont release .....am I missing something?

[Dennis Texas]

Originally Posted by rjgilge Have a 70 GT, that the front calipers are not releasing...completely rebuilt, seals, pistons etc...new master cylinder, cant seem to get them to work right...bled system several times....pedal seems right not hard...both front calipers are both sticking and wont release .....am I missing something?

looking over your replaced items I would guess 2 things rubber hoses from chassis to slave are swollen and need replaced and if thats not it then someone rebuilt the slave (disc) actuators wrong. Looking at your list the only thing not rebuilt is the rubber hose and the actual rigid tubing. there is something preventing bleed back to the master cylinder when you let foot off of peddle

[hrcollinsjr]

Originally Posted by rjgilge Have a 70 GT, that the front calipers are not releasing...completely rebuilt, seals, pistons etc...new master cylinder, cant seem to get them to work right...bled system several times....pedal seems right not hard...both front calipers are both sticking and wont release .....am I missing something?

Welcome to the list and glad to see you used the search feature before asking a question. If you had looked a little longer you might have found the answer you were seeking. To save you the trouble I'll tell you what the likely culprit is, the rubber brake hoses. They look fine on the outside but swell internally restricting the flow. Replace all three, same part for all three.

Harold

[Dennis Texas]

bet money on the rubber hose from chassis to the disc brake assemble pressurized when depressed just leak back when let off of pedal the hoses are swollen act like a check valve.

[Dennis Texas]

Originally Posted by hrcollinsjr the rubber brake hoses. They look fine on the outside but swell internally restricting the flow. Replace all three, same part for all three. Harold

see LOL he posted before I did thats your problem ..puts harold on can trust for help list

[ddoyle]

I had a friend tell me that he switched to DOT 5 brake fluid in his hobby cars and has had no more problems with sticking caliper pistons after sitting for over 1/2 a year at a time. Less hydroscopic? Thinking about giving it a try on the Alfa, 4 double piston calipers, can be a pain to free up after sitting!

Dan

[kent]

My front pass side sticks, I just replaced all rubber flex hoses and this did not help. What would be the next thing to check? I have never done any brake work so speak slowly Thanks by the way I drive this car 4-5 days a week its not a "sitter".

[BQS4]

If these are the original calipers to the car, then it's quite possible that the one caliper is gummed up and needs to be rebuilt or replaced. Your choice.

[kwilford]

Originally Posted by ddoyle I had a friend tell me that he switched to DOT 5 brake fluid in his hobby cars and has had no more problems with sticking caliper pistons after sitting for over 1/2 a year at a time. Less hygroscopic? Thinking about giving it a try on the Alfa, 4 double piston calipers, can be a pain to free up after sitting! Dan

I have done a bit of reading and there are a couple of good threads here on the topic of DOT 3 (and 4) brake fluids, which are glycol-based (and glycols absorb water) and DOT 5 brake fluids (silicon based, not hygroscopic).

Glycol brake fluid systems must be kept ABSOLUTELY airtight, otherwise the fluid absorbs the humidity in the air and causes corrosion, not to mention it will boil at lower than "normal" braking temperatures when "wet". Many modern master cylinders have a floating membrane on the master cylinder to minimize the contact between the fluid and air.

Silicon fluids aren't the "be all, end all" though. While they don't absorb water, their tendency to separate from water is actually a "bad thing", as ANY water in the system tends to accumulate in low spots and can cause even more severe corrosion that "wet" DOT 3 brake fluid.

The smart folks say, no matter which fluid is used, to drain, thoroughly flush, and replace the brake fluid at LEAST every three years, and more often if the car sits for extended periods. Some do so every spring before they go out on the road.

Many classic car owners have switched to DOT 5 fluid, mostly for reasons of less water absorption. Although they are SUPPOSED to be compatible, everything I have read says that the glycol fluid MUST be thoroughly flushed out (using Butyl Alcohol, NO PETROLEUM BASED FLUIDS, they destroy the rubber seals etc!!!) before switching to silicon based fluid. Many recommend also changing all the rubber seals and hoses before switching, to ensure that whatever fluid the rubber has absorbed doesn't contaminate the silicon fluid. And there is a "suspicion" that once a seal is saturated with DOT 3 fluid, it will react (as in swell or rot) with DOT 5 fluid.

HTH