Help; Rear brake caliper; piston boot

[jpulll]

In the middle of the rear brake job. Started twisting the piston in and the boot started twisting with it. Just got done with the other side and this did not happen, I know something is wrong and stopped ahead of time. Need some tips and tricks. My fear is the rubber is going to rip.

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[jpulll]

My thoughts are maybe pump the brake pedal so it goes back to the original position then try to break free the “stuck” rubber boot so it can spin freely? I’m just spit balling here.


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[Kevin C]

The boot need to get unstuck from the piston. Try to gently pull it back and work it loose. A shot of brake cleaner might help. Some brake assembly lube inthe seal is probably a good idea once you get it free.

[jpulll]

The boot need to get unstuck from the piston. Try to gently pull it back and work it loose. A shot of brake cleaner might help. Some brake assembly lube inthe seal is probably a good idea once you get it free.

Completely agree with you Kevin.

Do you think I need to try to break free both ends of the boot or do you think I could get away with the one end.


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[Kevin C]

You just need to seperate it at the top of the piston.

[Seerlah]

Spray silicone spray on the boot (also peel back on the very top and lubricate the inside at the top where the boot will rotate). You will then be able to twist it back to make it uniformed, and will squish down evenly when you compress the piston. Works for me every time this happens to me.

[jpulll]

Cool thanks guys, I’ll give it a go. Glad to hear this happens once in awhile and your able to get around it without having to rebuild it.


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[Kevin C]

Brake assembly grease is nice because it stays put and helps maintain a good seal to prevent corrosion. If there is a small amount of pitting in the piston it helps to fill the gaps. This is not the same stuff as caliper pin lube, this is specifically for the piston seals and boots.

https://www.google.com/search?q=brak...p0LVG1qEmiCz_M

[EuroxS4]

I normally run a pocket screw driver under and all the way around the boot once or twice closest to the brake pad and removed it .You have to do it everytime before your retract the piston. Piece of cake brake the 1 edge free and your good to go. I do it everytime as It normally happens 9 out of 10 times.

[Kevin C]

I normally run a pocket screw driver under and all the way around the boot once or twice closest to the brake pad and removed it .You have to do it every time before your retract the piston. Piece of cake brake the 1 edge free and your good to go. I do it every time as It normally happens 9 out of 10 times.

Its like its the parts have been baked together or something. Pretty much my experience,it it's not stuck its a surprise.

[jpulll]

So I was able to break it free. The problem now is the boot won’t slide in with the piston. So once I get the piston in, the boot slips over the piston. I tried wedging it back in and well it ripped. What to do.


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[jpulll]

Just went back out, and it is completely torn probably from the pressure. So I’m guessing I need to either rebuild it or get a new caliper. How easy is it to rebuild those calipers?


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[EuroxS4]

Gonna have to rebleed the entire brake system if removing piston to rebuild as you now have air the system and the car is unsafe to drive. This why i normally run the screw driver around the outer edge only closest to the brake pad if the rubber boot comes out of the other side or piston its just that much more work to get it fixed.

[jpulll]

I see what you mean. Lookin like I have some bench work ahead of me and it gives me a good reason to buy the power brake bleeder.

They make just a boot repair kit or an entire repair kit. My piston looked shiny clean so I’m under the impression I can get away with the boot repair kit.


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[EuroxS4]

Im not sure if you can get the boot only. If your gonna do it might as well replace the orings as well why do it half ass??

[jpulll]

So I’m trying to figure out this parking brake mechanism. I think mine is frozen in the tightened position and that is why I can’t seem to figure this out and the only way to free the cable is by cutting it.

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[jpulll]

IMG_0659.JPG

Where the red arrow is pointing, is that where you pry down so you’re able to remove the cable?


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[EuroxS4]

That cable looks like its seized or you have the ebrake up possibly. Normally you pry down and pop the ball end of the cable out of the bracket and remove the retaining clip for the ebrake cable.

[jpulll]

That cable looks like its seized or you have the ebrake up possibly. Normally you pry down and pop the ball end of the cable out of the bracket and remove the retaining clip for the ebrake cable.

Okay that’s what I figured cuz I’m wrestling with this mechanism and it won’t move at all. My e-brake has not worked for years so I know there is a good chance it’s frozen.


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[jpulll]

I ended up cutting the cable. The mechanism did not snap back into place like I pictured. It does move by hand strength but it definitely does not return to its resting position via the spring.

So...how do you rebuild the mechanism. It’s spring pressure, essentially 2 plates, 1 fixed, 1 moving. Is it as simple as getting a new spring and cleaning up the years of rust? Is there more to it than that?


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[Kevin C]

I think you are at a point where its going to be more cost effective to get a set of rebuilds and use those for cores. The shaft is probably rusted up and it may cost more in parts than its worth. I have some info on the B7 caliper, the parking brake mechanism should be the same.

https://www.audizine.com/forum/showt...rake-snap-ring

[Kevin C]

To add to that, perhaps consider B7 rear calipers and rotors? You can match them up with B7 fronts. :)

[Biged243]

I have a full front and rear b7 set. Fronts have Tyrol stiffening kit with ss lines.

[jpulll]

I thought about that but I just want to get the car back on the road. I already have all the pads and rotors, one side is already lubed up and on the car. So it would be more of a hassle to me than upgrading and buying more things. Next time maybe.

Spent some time this evening freeing up the cables preparing for a smooth replacement. Luckily nothing broke. Crazy how those clips that hold the cables in place are $20-$40.

Also went with the Cardone calipers from rock auto. Seems they are remand’d Lucas calipers from Audi. This is the only place I could get a core deal.


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