Lotus Elan

To Split (calipers) or not to Split, that is the Question

PostPost by: jbeach » Fri Sep 11, 2015 8:00 pm

Dear Brake Experts:

So I finally delivered my front calipers to my local Midas shop to have them rebuilt. I asked whether they could split the calipers and replace the O-rings. They said if the calipers are not leaking (they are not) don't even think about splitting them, as to do so is just looking for trouble.

I'm perfectly fine with this approach, unless any of you more mechanically-knowledgeable folks believe I should insist this be part of the rebuild.

Many thanks!

John
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PostPost by: mbell » Sat Sep 12, 2015 2:15 am

The main reason for splitting them is to make it easier to remove the pistons. If they are happy to remove the pistons with out splitting it should be fine. That's how I did my calipers, as ever probably just making life harder for myself...
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PostPost by: collins_dan » Sat Sep 12, 2015 1:22 pm

I had no need to split to remove the Pistons. No leaks before or after. Dan
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PostPost by: europatek » Sun Sep 13, 2015 12:12 am

I've split a few pair to rebuild and never had any trouble. Just make sure the rebuild kit contains the o-ring for the passage between the halves before you discard the old one. I've had kits with and without it.
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PostPost by: fasterbyelan » Sun Sep 13, 2015 11:09 am

europatek wrote:I've split a few pair to rebuild and never had any trouble. Just make sure the rebuild kit contains the o-ring for the passage between the halves before you discard the old one. I've had kits with and without it.


Paul Matty supplied me with the O rings when I re-built my calipers. I have never seen a kit with this part included (here in the UK).
Karl 8)

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PostPost by: Elan45 » Sun Sep 13, 2015 3:47 pm

Not so much of a problem with the front calipers. The rear ones, if stuck, as they usually are, I've always had to split,them, then use an internal pipe wrench to remove the pistons. I would source the O rings at some one like RD Ent, Dave Bean or one of the Triumph specialists. Never tried any of these suppliers for them, because I have a local source I've used since the mid-70s.

Roger
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PostPost by: john1180 » Sun Sep 13, 2015 4:50 pm

For stuck pistons, try adapting a grease zirc to the hose inlet and pump grease in to pop the pistons. I bit messy, but always works!
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PostPost by: Elan45 » Mon Sep 14, 2015 1:27 am

I knew someone would suggest the old grease gun method of removing pistons. My father taught me some 50 years ago, to never get any petroleum based solvents inside any brake fluid surface. I always use denatured alcohol or spray :"Brake Clean" to clean the cylinders so as not to contaminate them. I suppose some newer brake fluids may not be so susceptible to petroleum, but why take a chance..

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'67 Elan S3 SE upgrade to 26R by Original owner
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PostPost by: StressCraxx » Mon Sep 14, 2015 4:46 am

Elan45 wrote:I knew someone would suggest the old grease gun method of removing pistons. My father taught me some 50 years ago, to never get any petroleum based solvents inside any brake fluid surface. I always use denatured alcohol or spray :"Brake Clean" to clean the cylinders so as not to contaminate them. I suppose some newer brake fluids may not be so susceptible to petroleum, but why take a chance..

Roger


Roger,

I agree about the grease as a questionable choice. The grease may attack the o-ring, causing it to swell and eventually leak. Most of the caliper rebuild and o-ring kits now use EPR or EPDM elastomers. They will swell and fail with the oil in the grease.

Regards,
Dan
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PostPost by: UAB807F » Mon Sep 14, 2015 8:06 am

I used to leave them assembled and just remove the pistons until I got one pair that were very rusty. When I split them I found a "gooey mess" in the passageways, after which I've always split calipers. I have no idea where it came from, all I can add is that it had been hanging around unused for a while before I started on it.

Some of the UK Ebay sellers do the complete kit which includes the small square section ring you need.
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PostPost by: lotocone » Tue Sep 15, 2015 4:27 pm

Elan45 wrote:Not so much of a problem with the front calipers. The rear ones, if stuck, as they usually are, I've always had to split,them, then use an internal pipe wrench to remove the pistons. I would source the O rings at some one like RD Ent, Dave Bean or one of the Triumph specialists. Never tried any of these suppliers for them, because I have a local source I've used since the mid-70s.

Roger


I agree with Roger about the rear ones. I rebuilt mine a few years ago and splitting them helped a lot with the reassembly also.
Bob
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PostPost by: dgym » Tue Sep 15, 2015 8:55 pm

I've just done this job and was recommended by several experienced people to split them.
The rebuild was a lot easier, I am yet to re fit the calipers to see if i've ruined anything but it all went back together hassle free.
-Jim
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PostPost by: jbeach » Fri Sep 18, 2015 1:09 pm

Thanks everyone. VERY informative, as always!

I'm going to let my guys make the decision whether they'll split, but they've ordered the o-rings just in case.

I'm more inclined to just do it all now, but I'm trying to avoid getting sideways with my brake specialists before we even get started.

I'll give a report with some photos when they're done.

Best,

John
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PostPost by: elanner » Fri Sep 18, 2015 2:39 pm

Rotoflexible hasn't been around for a few weeks so I'll steal his thunder.....

I went over to his place last year to watch/learn how he was refurbishing his calipers. He had a neat setup to remove the pistons. He'd cut a bicycle valve from an old tube and fashioned it so that he could jam it into the bleeder hole. Then a few strokes with a bicycle pump and out they popped.

Nick
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PostPost by: potleyu18 » Fri Sep 18, 2015 3:56 pm

I Recently split the rear caliper to replace the pistons and seals without any issues and to do this without doing so requires a great deal of patience.

Steve
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