Rear Brake Caliper Rebuild-Restoration.

[AHM]

I spent a few hours reducing 2 sets to a pile of bits....

With 2 of the pistons there was no shifting them - My car pump got up to 100 psi, I put rhem in the vice to free them up (in the wrong direction) nothing doing!

A very simple mechanical solution - I put a bar into the bore of the piston then tapped in a cold chisel until it was wedged... rotate with stilsons and pull - They came out in one easy motion. The pistons were scrap anyway as they were clearly rusty.

Where can I get new -
Pistons
Square section 'O'rings

Ceejay - Is there any reason that you didn't get the caliper bodies zinc plated as well?

Simon

[robertverhey]

Try the fellows at big redd http://stores.ebay.com.au/Bigg-Red?_trksid=p4340.l2563
Might be able to help you (but none listed at present)

Rdent in USA http://www.rdent.com/ (scroll down on elan parts page)
Elan Factory in Oz http://www.elanfactory.com.au/pdf/produ ... 0parts.pdf
Ebay from time to time (where I got mine)

[ceejay]

No particular reason why I painted instead of zinc....I just liked the idea
of the red caliper paint.... I only gold zinc passivated the handbrake mechanism,
which looks really nice with the red paint.... the paint on the car is red also,
so it kind of matches.

Stainless piston source options:
1: Machine your self if you have a lathe and you are skilled at machining
2: Take old pistons to machine shop and get them to CNC to specs (Quick method)
3: Source from links and names already mentioned.
Ceejay

[DeanG]

I got my calipers back from the shop today. All 4 rebuilt for about $700. There is one thing that still needs to be replaced. Are the serrated screw and spring clip for adjusting the parking brakes available?

As an aside, the shop that rebuilt my calipers does lots of Mini work. The owner says that he splits all the calipers during his rebuilds, has been doing this for years and has never had a problem.

[Sea Ranch]

I have been led to believe that the specialized adjustment nut and clip for the park brake "tie rod" are not available as new parts.

I used a simple "metal loc" nut (like a nyloc nut but without the nylon) and this has performed acceptably for me, though doesn't quite look the part if a concours judge is sniffing around underneath

Randy

[lotocone]

Lots of very helpful info here. Thanks to Ceejay and everyone else who posted.

I just finished rebuilding my rear calipers and one of the stainless steel pistons was stuck. Air pressure plus heating of the caliper didn't help. Finally, put the caliper back on the car, bled the brake system quickly and pedal pressure got the piston out. The pedal was spongy but it still pushed it out. (Of course, the unstuck piston had go go back into the caliper to prevent the brake fluid from just squirting out).

I split he calipers because as Ceejay said, it's a lot easier to get the new rubber dust seal into the grooves in both the caliper and the piston. You have to look closely to make sure the seal is in the piston groove. Somehow I did a rebuild once many years ago with the caliper in one piece, but I have no idea how I did it ! A new rubber seal was added between the 2 halves and there hasn't been any leakage. I used the bolt torque numbers that Ceejay suggested for the 4 caliper bolts.

While separating one of the calipers, I damaged one of the handbrake adjustment rods. The replacement was $29 for something that is basically a fancy bolt, so I wish I had been more careful. Also the clevis pin that holds one end of the rod is an odd size - somewhere between 5/16" and 3/8". A friend with a lathe will probably make something that will work.

One thing that I noticed is that if moisture ever reaches a piston bore, I don't think bleeding will get it out. The bleeder is located above the piston bores and bleeding won't move fluid that is in a bore, which is a dead end. I think the bleeder is located on the caliper for bleeding air from the high point.

Again, this thread was very helpful to me. The job is fairly messy and frustrating, but I got it done and saved some money for other Elan parts.

Now I can take a drive and not have to worry about crashing into a defenseless SUV.

[ceejay]

Hi Guy's, happy to share and glad that this has helped many elan owners
with their calipers.
Ceejay

[Davidb]

I thought it was worth bringing this thread up to the 'top' since it is so useful-at least it has been to me over the past few days!

I would also like to put a plug in for silicone brake fluid-I have used it since the seventies in racing and road cars and have never had a problem-despite some of the outlandish stories there are on the web!
Here in Vancouver we have a pretty damp climate most of the time-much like the UK where I grew up. I found that wheel cylinders in cars sitting over the winter would seize up due to corrosion-not once they were converted to silicone though.
I recently bled the brakes in my DB2-all drums-and the five year old silicone fluid was still very good and despite sitting for extended periods the wheel cylinders never sieze.

[Project9]

Firstly a thanks to CeeJay- excellent! Words and pictures make this a really helpful description of the task.
I hope this will give the posting a bump .

As you might guess I'm doing a pair right now that I had thought were rebuilt but evidently had water close by while stored. Two smallish questions? Firstly what sort of fit of the swivelling clamps to the axle be? Mine seem very loose and secondly how do I remove the axle itself? Does it need to be drilled out?

Thanks

[ceejay]

Hi Guys.
Glad to be of help and share the info. Brake calipers can be a pain to work on, but once they are stripped cleaned, inspected and repairs done if required, they can be repainted and reassembled. A smear of rubber grease make the bits slide together easily.

[Brock]

Can the rubber boot seal groove(and the area that is covered by the boot) be protected with silicone brake grease -- or rubber grease? This is my plan. Anything coating with a film thickness will stop the piston from moving -- especially on the fronts. (Early brakes here). I was planning on Permatex brake grease -- which is rubber safe.

I sanded mine clean and converted the rust with Ospho (I adore Ospho). Iron oxide becomes magnetite -- and magnetite is stable.

All of my cylinder bores were perfect, but all of the areas covered by the boots were rusty and seized the pistons. This is dumb.

Top tip: Take an infrared thermometer along to check brake temps. Thus will identify a just barely stuck piston.

[Sea Ranch]

For what it's worth . . .

I am persuaded that if the brake system is renewed well and then the brake fluid completely flushed/replaced each year, we will have no more corrosion, no broken-down/deteriorated rubber and a brake system that will last our lifetime (minus pads and rotors, of course).

YMMV, this may be fake news, et cetera. But I'm following this advice anyway

Randy

[Brock]

Yabut my rust problem was all 100% outside of the seals... The main seal groove was perfect. This car had its fluids changed very often as it was on the Wet Coast. The rust came from without, not within. I'm in the desert now, so I may not need to worry, but still...

[ceejay]

Whenever I have dismantled brake calipers, firstly, they are dismantled, then thoroughly cleaned, inspected, bead blasted, and then repainted with high temp caliper paint.
The groove where the protective rubber boot locates can corrode, but the calipers on my car are OK, no excessive corrosion.
The bores of the caliper can show corrosion, but with chemical treatment to halt the action it should be OK, its the square shaped rubber nitrile seals that make the pistons work, they are not like the pistons in the engine that have rings for compression, and you'd be surprised how loose they are in the caliper bore with out the seals.
To dislodge stuck pistons, they can be either forced out with hydraulic pressure or air pressure...BE VERY careful with both, especially with air pressure, wrap the caliper bodies (half) up in cloth before applying any pressure, because the piston will come out of the caliper body like a missile when it lets go.

Working on brakes is not really all that difficult, you just have to be really pedantic about how things are re-assembled, making sure that all seals, joints, washers are in perfect order. Your personal safety depends on it.