Rear Calipers Options

[lsintampa]

75 914/4 2.0

I've rebuilt a small number of calipers over time - it really isn't my forte, but simple enough to do.

Or so I thought.

I'm not sure that I even understand how the rear calipers work on this car. I've never seen pistons screw on and off from the cylinders.

In any event, I'm assuming that the adjusting nut on the outside half needs to come out so I can replace whatever o-rings are under there.

I've soaked this puppy in blaster for two days. I can turn the large nut using a 1/2 inch socket, but then you can't hold the bolt steady and the whole thing turns.

I can barely manage to get a wrench on the nut and then use a hex wrench but the bolt just won't budge.

Question is, since I can turn the whole thing with a socket, would it be OK to adjust the piston that way? I'm worried that with all the turning that the o-rings may be not so good under there.

And just as a side, how the hell does that piston even move? It doesn't seem that it can, so I'm really confused on how this whole system works.

And as another side, what other calipers may work on the back beside these puppies?

Thanks,

Len

[mepstein]

PMBPerformance.com has some good video's on their site and there is a reason why Eric keeps busy restoring calipers on our cars.

[brant]

no other caliper on the back will allow you to have a parking brake

the video will help
lots of pieces


there is a small circlip (some times called an E-clip?) on the nut/bolt you have pictured. Yours may be rusted mostly away but may have enough left to prevent the nut from screwing off?

take a dental pick and chase the thread on the center bolt. You should find the void where the thread stops and the C-clip is supposed to snap on.


brant

[JawjaPorsche]

Here is Eric's video on rear brakes:

http://www.youtube.com/watch?v=dm_DnizKOZM

[Eric_Shea]

I've soaked this puppy in blaster for two days...

...would it be OK to adjust the piston that way? I'm worried that with all the turning that the o-rings may be not so good under there.

After soaking in PB blaster for two days, the o-ring is shot anyway. In for a penny in for a pound right now. Watch the video and let me know if you have any questions.

[lsintampa]

I've soaked this puppy in blaster for two days...

...would it be OK to adjust the piston that way? I'm worried that with all the turning that the o-rings may be not so good under there.

After soaking in PB blaster for two days, the o-ring is shot anyway. In for a penny in for a pound right now. Watch the video and let me know if you have any questions.

Fantastic video - I'll be watching it several times before I'm done for sure.

The caliper in the photo had no c-clip and the adjustor and nut was basically one piece. I managed to get a small 1/2 inch (very thin) wrench on the nut and was able to brake the adjuster loose. YEAH! So the outside piston and adjustor are out!!!

The other side did have a c-clip and the nut came off easily. But I'll get to that side after I get this one done. Just wanted to see if I was in for more drama.

That's the good news.

I'm still on the same caliper (left rear) now and I'm trying to get the inside adjuster out, but that's not working at all. It was rebuilt at some point in the past, I can tell because the adjustor cover has notches in it from someone knocking it off - as shown in the video. As well the hex hole on the cap is stripped, so there really isn't any way for it to come off at this point. All I can say at this point is that using a cold chisel on the thing is just mangeling up the cap to the point that there isn't an surface area on it to get a good bite.

Can that thing be ground or drilled out or what? Afraid it isn't comeing off by banging on it any longer.

Video is top notch! Very helpful.

Thanks,

Len

[brant]

The notches don't necessarily mean it was rebuilt in the past

that "cover" has to be removed to set the venting clearance on the car. rear brake venting clearance is a maintenance item and if not set periodically the parking brake will loose effectiveness and the brakes in whole will be less effective.

[steuspeed]

My rear brake caliper thread.

http://www.914world.com/bbs2/index.php?sho...;hl=rear+brakes

[Mblizzard]

First let me say that other than using PMB products I have no connection with them. I spent many years working in my farther's machine shop. I have done everything from a simple valve job to rebuild marine Diesel engines of which the scale of we're just mind boggling (think pistons the size of manhole covers Really!). But one of the things that frustrated me the most was the 914 rear calipers. Each of us can watch the video and think it seems easy. For some it is. But I just could never get it right. When it came time to replace them on my most recent car, PMB was the right choice. I have no doubt that many here are much more skillful than I am or that rear calipers may just be my weak point, but sometimes it is best to leave it to a true expert. I don't mean to imply in any way that you are not capable of completing the task. But In brakes, PMB is the expert without question.

[76-914]

Eric's kit installed. If'n I can do it, so can you. Don't throw away the 13mm low profile nuts. They're "weren't" included in the kit.

[Mark Henry]

If your the DIY type get Eric's complete caliper kit, for the bodies and bits all plated and the rebuild kits you can't beat that price.

[lsintampa]

Thanks all,

The video was great, but the issue(s) that I'm having have more to do with stuck caps / nuts on the adjusters.

I managed to get the outside adjusters freed up, the inside caps are a challenge yet, but I do have a plan to deal with them.

I'll shoot Eric a email and let him know what bits and pieces I need to finish the rebuild. He's been a great resource for me.

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