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Posted by: VWTortuga336 Feb 20 2015, 07:21 PM

Still working on getting my '74 back on the road after it has been sitting for 10+ years. I'm now looking into the brakes. I have no experience with them and I am about to start reading up in my Haynes manual, but I also wanted to get input here before I dove in.

First things first, the rear passenger side caliper is totally stuck (I pushed the car into the garage, but can't even come close to getting the tire to turn by hand). With the tire off, I can see that the pads are closed tight against the rotor. What would cause this, i.e., what should I be looking for and what should I be doing to correct it?

I plan on also pulling out the master cylinder for rebuild and figuring out why the hand brake doesn't work. What else should I be doing in my "brake revitalization"?

Posted by: mobymutt Feb 20 2015, 07:30 PM

You can look at the top video here:

http://www.pmbperformance.com/video.html

Posted by: type47 Feb 21 2015, 06:16 AM

don't think MC rebuild kits are available. My recommendation is to buy Eric Shea (pmbperformance) rears and rebuild the fronts. Is you braking system still together/intact? Before you open the brake system, there is a trick to help get the pistons free for the fronts.This works only if you still have fluid in the system and not opened it. Remove the front pads and have some wood shims available. Put shims (sorta thick) where the pads were and you can pump the brake pedal to push the pistons out of the caliper. You don't want to push any piston completely out of the caliper 'cause if you do, you won't be able to push any remaining pistons out. Gradually insert thinner shims and push pistons out (but not completely out). Eventually you'll get to the point where the piston touches the rotor and of course can't be pushed out any further. Then remove the calipers and use compressed air to push pistons out of caliper. Watch that you don't crush your fingers as the pistons pop out. Cushion the pistons with wood or rags. In my opinion, the rears are complex enough (for me at least) to get a pro rebuild (exchange w/ a pair of pmbperformance calipers)

Posted by: thieuster Feb 21 2015, 07:22 AM

On the other hand... Be very careful! The brake hoses are pretty old I assume (after 10 yr standing) and although perhaps sound looking on the outside, they can have collapsed on the inside: when you push the pedal, the fluid will travel to the calipers, but it can not return! Thus locking the brakes. Don't ask how I know...

Menno

Posted by: VWTortuga336 Feb 21 2015, 08:19 AM

I've done some reading on Eric's brakes and I'm thinking that's the way to go.

I'm still wondering, what would have caused the pads to stick like this? Any chance I can just unstick the pads and be good to go, or will I need to do a complete rebuild?

Posted by: mepstein Feb 21 2015, 08:48 AM

They are the most important safety device on the car so spending the money to have PMB make them perfect is really a great investment.

Posted by: JawjaPorsche Feb 21 2015, 08:59 AM

New hoses and PMB is the way to go.

Posted by: type47 Feb 21 2015, 09:36 AM

water in the brake fluid (could happen if fluid isn't changed) could rust the piston and caliper hindering free movement of the piston in the caliper bore. Like stated above, a collapsed brake hose prevents relief of pressure preventing piston from moving. I think even if you unstick the piston it should be rebuilt; rebuilding is not that hard and the confidence of having "new" brakes is reassuring.

Posted by: VWTortuga336 Feb 21 2015, 10:12 AM

That confirms what I was thinking. Just wanted to make sure I explored all my options.

So here's what I think my to-do list is:

1) Pull all calipers
2) Send rears to Eric for rebuild
3) Rebuild fronts
4) Pull MC & pressure regulator for clean up
5) Flush lines

Is #5 a possibility, or am I stuck replacing them all. If they can be flushed/cleaned, what would be the best way to do this? Is there front caliper rebuild kits I should be sourcing?

Posted by: type47 Feb 21 2015, 10:40 AM

link to hoses, rebuild kits, and pads

http://www.pmbperformance.com/914brake.html

Posted by: BeatNavy Feb 21 2015, 11:29 AM

Happened to the both front and rear calipers of both 914's I've purchased that had been sitting for years. You need to remove the pads, remove the calipers, and assess if they can be rebuilt. There are good caliper rebuild kits available, and Eric's video on the rear caliper rebuild process is excellent. I successfully rebuilt my rear calipers and destroyed the front trying to force the piston out of the bore (and ended up buying freshly rebuilt). The rear pistons can simply be cranked out with the adjuster. Getting the pistons out of the front caliper is a little trickier and can be dangerous if you use something like compressed air.

I also agree about getting new brake lines. Good luck getting that one line in behind the engine mount. It helps to be a contortionist on that one

Posted by: VWTortuga336 Feb 21 2015, 06:45 PM

So, I got a little too excited and didn't reread your post before I removed the rear calipers. The resevior is full of fluid but with the rears off, is my system now open, meaning I cant use your method of removing the front pistons? If so, how should I do it? Could I just buy caps for the lines?

I should also point out that all the pistons look pretty rusty, so I'm not sure they'll move from the pressure of the brake fluid.

Posted by: PlantMan Feb 21 2015, 10:55 PM

I purchased a cap for my rear lines, actually capped at the master cylinder with a single cap. I removed the pads from the front cals first then pumped the brakes for a while. The pistons eventually broke free and closed on the rotors since the pads were removed. I unbolted the cals and used compressed air to drive out the pistons all the way. Worked like a charm.

Posted by: brant Feb 21 2015, 11:11 PM

You can't go wrong with eric.
And if you do it yourself the video is excellent also
The rears are not really hard to do.
I've done 3-4 sets over the years.

Posted by: VWTortuga336 Feb 22 2015, 04:19 PM

Now I've got all the calipers off and used the wood shim trick to get all 4 pistons on the front calipers to close onto the rotors. How do I get them all the way out now? Where/how do I apply the compressed air?

Posted by: BeatNavy Feb 22 2015, 05:11 PM

The rear caliper pistons will come out using the adjustor. It's pretty straightforward. Check out Eric's rebuild video.

Removing the front is tricky (at least for me). If you use compressed air, BE CAREFUL! I ended up breaking my caliper, although you can end up breaking bones if it goes bad. I've heard using a grease gun works. It may be messier, but it's a lot safer apparently.

Basically you use air (or grease) on the brake line fitting until one piston comes off. Again, be careful -- it can come flying off! Then you have to put that piston back on and hold it in place with a C Clamp (or something) so you still have pressure to get the other piston out. Do a search on the exact procedures, but that's basically it: use the brake line fitting; get one off; clamp it back on; apply air or grease until the second one comes out.

Posted by: VWTortuga336 Feb 23 2015, 08:03 AM

Could I connect the calipers back to the brake lines and continue to use the brake fluid pressure to push them out?

Posted by: type47 Feb 23 2015, 09:22 AM

yes if you bleed the brake system. If you simply reconnect the lines, you'll have introduced air into the system. If you have air in the system, you'll compress the air bubbles when you depress the pedal. With no air in the system, you'll transfer the brake pedal action to pressure in the fluid instead of pressure on the air bubbles.

Posted by: Eric_Shea Feb 24 2015, 10:32 AM

You need to have all of your caliper bodies replated at this point. Brake fluid is hygroscopic. Rust never sleeps. If you want them to last, they need to be replated. ATE did it for a reason and, I'll guarantee you that reason wasn't "bling".

For the rears; I'd suggest you watch the video as everyone here's mentioned.

Posted by: VWTortuga336 Mar 2 2015, 09:13 PM

Eric, I think these calipers are outside of my comfort zone for me to rebuild myself. I sent you a PM, hopefully you can save them.