924Board.org

maireeka · Joined: 29 Aug 2004 Posts: 299 Location: North Alabama

Hello, I just started my brake job and already have been stopped in my tracks. I'm trying to remove the 19mm bolts that hold the caliper onto the mounting bracket. The top one came off fairly easily, but the bottom one won't budge. I've got a pretty long torque wrench on there, but I don't have any leverage, and stepping on it only makes it worse I think.

I'm afraid i'm going to round the bolt and then it will all be over. Anyone have a good way of getting this bolt off? It's torqued to a really high number I think, and that's probably why it's so hard to get off.
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1977 Porsche 924 red and READY!

leadfoot · Posted: Wed Mar 23, 2005 3:33 pm Post subject:

Apart from squirting some penetrant onto it and leaving it overnight there's not much you can do.
Although you may have some success by trying to tighten it even further than it is now, I know this seems weird but it can crack the seal that's built up overtime. You only need to make it budge a little.
I'd be more woried about snapping the head off. If your worried about stripping the head then make sure you using the right size good quality 6 point socket. A poor quality socket will not be the right size due to casting and twelve points are reknowed for stripping tight bolts.
Last resort would be to drill it for an extractor. Might be a consideration if the bolts that old though, worth replacing every now and then since the're cheap and in an important location.
Leadfoot

Lizard · Posted: Wed Mar 23, 2005 3:56 pm Post subject:

use a box end of a wrench on it, not a socket, way less likely to strip
then use another wrench as a cheater, or hit that wrench with a hammer to loosen
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3 928s,

maireeka · Joined: 29 Aug 2004 Posts: 299 Location: North Alabama

I still can't get that bolt. I'm going to sears to buy a good 19mm socket and a good 19mm wrench...

on another note, I got the other side almost completely done, All i have to do is attach the brake lines. The new rotors and caliper look sharp!

lastly, a question. when I put the new caliper onto the rotor, I kinda had to push it, like the pads were nearly too thick. Once I get it hooked up, bled, and I push the pedal a couple of times, the caliper will loosen up so the wheel can turn easily, right?
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1977 Porsche 924 red and READY!

Smoothie · Posted: Thu Mar 24, 2005 2:29 am Post subject:

I was under my car just yesterday messing with the rear wheel camber. That involved some M12 bolts with 19mm heads that were rusted in tight. I have a relatively extensive range of torque wrenches to choose from and went for the largest one with 40-250 ft-lb range and approx. 2' long. Fun stuff - little clouds of rust dust shot out as the bolts broke loose.

Anyway - one of the heads wasn't in great shape and the 19mm socket was slipping on it, so I tried the rough equivalent in SAE, the 3/4" size. That's slightly smaller than 19mm so it fit closer - in fact had to be lightly hammered-on to the bolt head. That held it and got it off.

On the pad replacement - You'd normally squeeze the piston into the caliper before putting the new pads in. I've used anything from a screw driver to Vise-Grips to large channel-locks to a c-clamp to get it done. (Check the level in the brake fluid reservoir as you do it.) If the piston won't go in, you might have a rust problem there. If there is no rust problem, disk brakes are self-adjusting and should be good with a few pumps of the pedal.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

MALUKIA3 · Joined: 13 Dec 2003 Posts: 82 Location: NY

Just rebuilt my calipers last weekend, they came off easily w/ a box-end. You could try to heat the bolt with a blow torch. The heat makes the metal expand/contract and will usually let you bust it loose.

Didn't see what all you're doing but you can replace the pads without removing the caliper.

Don

79 n/a

CMXXXI · Joined: 05 Nov 2002 Posts: 1939 Location: Vicksburg, MS

First time I ever removed the calipers, I used the wrench included with the car's tool roll, which is supplied for use as a lug wrench. It's a long tube with a 6-point socket cast/stamped onto/into one end. If you have this tool, you can insert the included cross piece, and then get extra leverage with something slipped over the end.
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'79 Eurospec 931

maireeka · Joined: 29 Aug 2004 Posts: 299 Location: North Alabama

I'm screwed. I tried torque wrench, regular ratchet, box end wrenches, all in both 19mm and 3/4 inch. I tried the 3/4'' with the torque wrench, thought I had it turning just like the other three bolts (which came off fairly easily), and it rounded off. Now anything I try just makes it worse.

If I can't get this bolt off, I can't drive. I really needed to finish the front brakes today, and now I can't make any progress. I don't know what to do, I'm carless until I solve this problem. I don't have a torch, or else I'd try heating it and then removing w/vice grips or something.
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1977 Porsche 924 red and READY!

Smoothie · Posted: Thu Mar 24, 2005 5:12 am Post subject:

Next thing I'd try would be large visegrips with sharp teeth (resharpen them with a file if you have to). Clamp them on extra tight and oriented so you'd be pushing or hitting the release lever side of the handle to loosen the bolt (if put on the other way and you hit it, they'll just pop right off of the bolt). Then stand back and try smacking the visegrips with a hammer or mallet to loosen.
Pics showing the wrong, then correct way to attach Vise-Grips for smacking to loosen a bolt -
http://pg.photos.yahoo.com/ph/smoothies931pics/detail?.dir=/341f&.dnm=ecfd.jpg&.src=ph
http://pg.photos.yahoo.com/ph/smoothies931pics/detail?.dir=/341f&.dnm=80bf.jpg&.src=ph
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

maireeka · Joined: 29 Aug 2004 Posts: 299 Location: North Alabama

Got it, probably thanks to smoothie's method. The vice grips broke it loose then I could use the torque wrench once it could turn.

Here's before and after shots of the front brakes, now with rebuilt painted calipers and new cross drilled brembo rotors.

before:

after:

Now that the new calipers are put on, I need to attach the lines. Is there a good way to take the brake line off of the old caliper and attach it to the new one without getting brake fluid all over everywhere?
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1977 Porsche 924 red and READY!

Paul · Posted: Thu Mar 24, 2005 6:06 pm Post subject:

Sure, grab a hunk of wood about 16" long, place one end on the brake pedal, the other end on the front of the seat. Then slide the seat forward just enough to move the brake pedal about an inch or so.

This covers the inlet from the reservoir to the master cylinder, so brake fluid will not drain from the reservoir while you have the lines open.

Then put a box wrench on the caliper's bleed screw, then put a hose on the nipple of the bleeder and open the bleeder. This will vent any brake pressure.

Then unhook the hose. It will drip some fluid so be ready.

And replace, don't reuse those hoses. They are not to be used if they are more than 10 years old.

maireeka · Joined: 29 Aug 2004 Posts: 299 Location: North Alabama

Would it be okay if I used the hoses until new ones came in the mail? I kinda need this car, and didn't know to replace them until right now.
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1977 Porsche 924 red and READY!

Paul · Posted: Fri Mar 25, 2005 9:05 am Post subject:

Sure they will work, but your brakes may be mushy.

Also why don't you paint the rear dust covers while you're in there? They are really rusty!

maireeka · Joined: 29 Aug 2004 Posts: 299 Location: North Alabama

Yeah, it's a little mushy right now. Stops a LOT better than it did, though, even though the rears haven't even been messed with. When I get the right tools for the castle nut on the rear, I'm going to get new lines, and I'll probably paint the dust cover since I've got some experience with the fronts and could get it done quickly.
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1977 Porsche 924 red and READY!