REAR CALIPER PARKING BRAKE DISASSEMBLY

PostPost by: gearbox » Fri Nov 16, 2012 11:39 pm

Working on my rear calipers and looking to fully disassemble caliper and parking brake "wings". So far everything came apart with a little heat soaking, penetrant, air pressure, and gentle persuasion. Finally got to the parking brake wings and I think I know what to do, but wanted to double check before committing. It appears that they are two pivot pins pressed in to the main housing. The pins have threads on the inside which I assume is used to pull the pins out. tighten a screw in the pin, heat soak, and use a slide hammer attached to the screw to bang it out. I used a 10-32 screw and it appears to be the correct thread. Just want to make sure this is the way to pull these pins out and if there are any other tricks. Also, I would like to split the caliper which I know the factory manual says is a no no. But I have done this many times on other calipers with no issues. I just need to know the size and material for the two "O" rings that seals the fluid passages or better yet, if anyone sells them. My TTR rebuild kit did not have these O rings. Thanks Allan

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PostPost by: lotocone » Sat Nov 17, 2012 1:50 am

Allan,

The O ring seals are available from Dave Bean and RD. They have worked for me with no leaks.

Not sure about removing the pins. I'm curious to know about this too.

Bob
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PostPost by: billwill » Sat Nov 17, 2012 1:59 am

I think I've taken those pins out in the past, but I'm blowed if I can remember how I did it.

Be aware that they might only come out in one direction. It might be push rather than pull.

You don't need to take them out to get the pad shoes off, of course.

Here's a thought:

Rather than a slide hammer, find a bit of tube bigger than the pin, then a big washer to cover the outward end of the tube, put a nut near the head of a long bolt of the right thread, then poke the bolt through the washer and tube and screw it into the pin until it bottoms, then hold the head of the bolt with a spanner and turn the nut and it should (I think) gently pull the pin out of the casting.
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PostPost by: gearbox » Sat Nov 17, 2012 2:07 am

billwill wrote:I think I've taken those pins out in the past, but I'm blowed if I can remember how I did it.

Be aware that they might only come out in one direction. It might be push rather than pull.

You don't need to take them out to get the pad shoes off, of course.


They look to be one way in and out as the other side is blind (no holes). I'm chasing the threads with a 10-32 tap and they work. Interestingly enough, when the tap bottomed, it started to rotate the pin, very good sign. I have a slide hammer with a vice grip that I would use to coax them out. I am also thinking of making a "U" channel with a hole where I could put the 10-32 screw through, screw into the pin, and use a nut on top of the Cannel to withdraw the screw with pin. Just have to find a long enough 10-32 screw. I fully understand that this is uneessary to remove the pads as I have already removed them, but this is my anal retentive nature of completely disassembling everything and de rusting them in Muruiatic acid and repainting or plating them. I'm 90% certain this is the way to do it unless anyone else has any better ideas. I'm soaking the assembly in PB Blaster and will try in the AM. Wish me luck. Allan
Last edited by gearbox on Sat Nov 17, 2012 2:11 am, edited 1 time in total.
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PostPost by: billwill » Sat Nov 17, 2012 2:09 am

See the extra thought that I put into my message while you were typing yours.

:lol:
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PostPost by: gearbox » Sat Nov 17, 2012 2:14 am

billwill wrote:See the extra thought that I put into my message while you were typing yours.

:lol:


Good idea about the tube, I think I have some 1/4" round that I could cut down. I'm searching for a 10-32 nut at the moment. Thanks Allan
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PostPost by: billwill » Sat Nov 17, 2012 2:15 am

Hmmm, if its a blind hole at the back there is a faint possibility that the bottom end of the pin is threaded and screwed into the blind hole. Strange way to do it though.

Then you would need to tighten a nut hard on your bolt against the pin (while holding the head of the bolt), possibly with a washer spacer, then use the nut to unscrew the pin.
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PostPost by: gearbox » Sat Nov 17, 2012 2:58 am

Mystery solved. Taking Bill's suggestion which was a easier version than I was contemplating, but same thought pattern, I cut a 1/4" tube about 0.5", found a washer, a 10-32 1" screw and nut. Screwed the nut all the way up the screw, inserted a washer, tube, then screwed the assembly into the pin. Holding the screw steady, I loosened the nut which drew the screw and pin upwards.

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The initial tug was hard, but soon as it broke free from the rust and corrosion it pulled up with no heat or further persuation. I used a screw driver under the pin to coax it along the remaining way. The pins were surprisingly free of rust, some gunk, but that was about it.

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Thanks Bill, that was a great idea, and I had all the parts handy. Now to dunk the parts and wait for rust free parts by tommorow AM. So how much is Bean and RD getting for these o ring caliper seals these days? $100 lol. Thanks again Allan
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PostPost by: Bud English » Sat Nov 17, 2012 5:26 am

From RD

"Ref. 26J4908 Caliper Cross-Over Seal $2.50 each
The small square-section ring seal fitted between the two caliper halves. If you split the caliper you should replace this seal. One seal required per caliper. "

I did this whole exercise earlier this year. I caught this thread late or could have helped with your earlier questions. Did you see much wear on the pins that you pulled?
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PostPost by: gearbox » Sat Nov 17, 2012 5:48 am

Bud English wrote:From RD

"Ref 26J4908. Caliper Cross-Over Seal $2.50 each
The small square-section ring seal fitted between the two caliper halves. If you split the caliper you should replace this seal. One seal required per caliper. "

I did this whole exercise earlier this year. I caught this thread late or could have helped with your earlier questions. Did you see much wear on the pins that you pulled?


Hey Bud, That's good to know, I was going to order RD's hub puller anyway. Square rings huh?, that's a first, usually on all the calipers I pulled apart, they were O rings to seal the port. Common engineering sense dictates that a O shape would be more stable vs a square, but if it works, it works. Wonder what the was the engineering behind that?

The pins look good, both pins have a large diameter of 0.328" and a reduced diameter of 0.308" on one and 0.306" on the other. Both fit the new pads tightly so I'm guessing the 0.002" differential is nominal. What do you think? Thanks Allan
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PostPost by: gearbox » Sat Nov 17, 2012 6:52 am

Bill;

What torque setting did you use to bolt the caliper halves back together? The factory manual is silent on this as they warn against taking these apart lol. Thanks Allan
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PostPost by: lotocone » Sat Nov 17, 2012 11:01 am

Allan,

I used about 35 lbs ft for the 3/8 in. bolts and 18 for the 5/16 in. bolts which was within the suggested range in this previous thread on rear caliper rebuilding. It has worked for me. elan-f14/rear-brake-caliper-rebuild-restoration-t22999.html

The rubber O rings are square in cross section only. Their overall shape is round.

Thanks for posting pictures and additional info about removing the pins. Let us know how the rebuild goes.

Bob
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PostPost by: gearbox » Sat Nov 17, 2012 12:57 pm

lotocone wrote:Allan,

I used about 35 lbs ft for the 3/8 in. bolts and 18 for the 5/16 in. bolts which was within the suggested range in this previous thread on rear caliper rebuilding. It has worked for me. elan-f14/rear-brake-caliper-rebuild-restoration-t22999.html

The rubber O rings are square in cross section only. Their overall shape is round.

Thanks for posting pictures and additional info about removing the pins. Let us know how the rebuild goes.

Bob


Bob;

Thank you, yes I did find CeeJay's thread when I did my pre search for this topic. It was a great write up and the only one I found that documented the procedure pretty much. But the thread skipped over some steps, one of them being removal of the Parking brake wings. I realize that much of the rebiuld is straight forward, and if you had done this as many times as CeeJay, you take things for granted, and while I had done numerious rebuilds on Porsche's, Jaguars, and others, this was the first time I had encountered this set up. So instead of screwing it up somehow, I decided to ask the collective wisdom of this forum. I am documenting my build on this site at http://www.lotuselan.net/forums/elan-f14/long-and-winding-road-best-taken-elan-t25723.html
and on my own website http://www.TheLolaRegistry.com just look under project cars and scroll though all the fun I am having, 20 cars and counting, including 2 Elans. Unfortunately, I work overseas, so I only get home twice a year for a month or two, so while I do get a lot done, it will be in stages. And Sandy didn't help either after coming home to no power and no gas lol. But things are getting better, doing a lot of inside work and hope to get her into paint by the Summer. I just have a ton of parts to order or fabricate as this one is a real basket case. Thanks again for your input, it was greatly appreciated, Allan
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PostPost by: CBUEB1771 » Sat Nov 17, 2012 1:21 pm

The slide hammer approach works well. I made an adapter with a #10-32 set screw in one end and threaded the other end to suit my slide hammer.
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PostPost by: AnthonyBelcher » Sat Nov 17, 2012 2:00 pm

Hi there
Not wishing to appear think but can you please tell me what a slide hammer is as I've not come across that name before.
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