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MG TD TF 1500 - To sleeve, or not to sleeve

I'm starting on my '53 TD's brakes. What do people recommed regarding brake cylinders- to resleeve, to repair or to replace?
Ira Spector

Hi Ira,

I resleeved my car with stainless sleeves about 10 years ago.
I have just today finished reconditioning the brakes. The cylinders were leaking and I removed and cleaned them and replaced the cups. The sleeves were in perfect condition and will probably last longer than me.
So as far as I am concerned stainless is the way to go.

Cheers,

Paul.
Paul van Gool

Paul,
Did you sleeve the Brake master cylinder and /or the brake cylinder. I took the decision to make new pistons from stainless as the bores were ok but the steel pistons corroding during periods of non use, and I did not think there was enough material in the casting to sleeve. Done this several years ago and no problem since. Of course I only did the front cylinders as the rear are not straight forward. What did you do.
David Tinker

During the restoration of my TD I also sleeved all 6 wheel cylinders and the master cylinder and am entirely satified with the result.
Phil Stafford

Hi David,
The master cylinder was sleeved in brass by a previous owner. I did the 6 wheel cylinders in stainless. You are certainly correct about the steel pistons corroding as one was completely seized up. I managed to remove the piston by screwing in a grease nipple and pumping it out with the grease gun. I cleaned the pistons up with a wire brush and coated them with rubber grease in the hope that they will not corrode so soon again. There is probably a lesson here for all of us. I will take out the pistons and clean them up every 5 years or so. Thanks for your input.

Cheers,

Paul.
Paul van Gool

Have had good luck with brass sleeved masters from White Post Restorations. One of the 4 front cyls. they did leaked-not sure if a problem with the sleeve installation, surface finish, or my assembly. I did use silicone brake fluid, which they advise against. The rear cylinders are really cheap for new- I think $40 or so, so why bother with sleeving? The last new ones I saw also have an additional seal on the outer piston. You still need to buy the repair kit, as the outer rubber boot is not included with the new cylinder. Sealing against outside moisture is virtually non-existant on the front cyls. The steel pistons corrode and stick to the pot metal bodies in short order in our humid climate, unless the car is driven routinely. I feel any kind of sleeve in these will last longer than the bare pot metal.
George Butz

Several years ago I re-sleeved all of my original wheel and master cylinders myself. I does take some machine skills and the right equiptment plus the brass tubing. Bored the cylinders to 1.0" ID and sleeves .997" OD, bonded sleeves in with special Loctite adhesive.
Sleeve ID is .875", which was then Sunnen fine honed to a cross hatched finish. (not polished) Inlet hole was redrilled and cleaned.
These have never leaked or shown any sigh of corroision using Castrol Dot 3 brake fluid. Don't use silicone brake fluid as rubber seal compound is not compatible with it.
If you live in a humid climate, flush and change the fluid every few years. This eliminates the corroison in alum. cylinders. Brass is better.
I am sure SS is great for this application, but I find it too hard to machine and finish, plus the tubing is scarce and expensive.
If your not into rebuilding your original parts, buy new ones.

colin stafford

Hi Colin
I am considering sleeving an MGA master cylinder for my sons car (sorry about being on the wrong BBS)and was wondering about machining fit, when I spotted your message. I was under the impression that a slight interference fit would be required (1 or 2 thou') but I notice that you used a clearence fit + loctite - is this the case and what grade of loctite did you use?
Regards
Tony
Tony Mitchell

Hi Tony, I have just sleeved a brake master cylinder on an MGA 2cam using stainless. I use a slight interference fit and use loctite, with adhesive grooves machined on the o/d of the sleeve every 15mm. The sleeve should not push out as the assembly is retained with a circlip.
David Tinker

First of all lets define an interference fit of diameters. If you have an interference fit" the ID is less than the OD or vice versa. You would have to either chill or heat the parts and use the coef.of expansion to assemble and create a tight fit union.
When you use adhesive you must have a "glue line" clearance of a few thou. for the adhesive to work. A tight fit will scrape the glue line of the mating surfaces during assy. I have use .00l" clearance (slip fit) with Loctite 620 Retaining Compound. This has excellent filling properties and high heat resistance up to 200 deg C. I would reccommend the appropriate primer and cleaner from Loctite. NOTE: Take care to get parts together quickly if you use Loc. 620 and brass sleeves as the copper in the brass is a catalyst for the adhesive and the setup time is "QUICK". After assy. I cooked them in an oven for 2 hrs at 200 deg F.
colin stafford

Colin, Perhaps I should have told the whole story. As well as an interference fit I machine adhesive grooves on the o/d of the bush 0.005" deep and 1/4" wide spaced every 1/2" or so. Prior to assembly I put the sleeve in the freezer overnight. I always use solid stainless bar from which to machine the sleeves.
David Tinker

David.....Wow! that seems like a lot of unnecessary work to make brake cylinder sleeves. 7/8" ID brass tubing is so readily available. These things do not see any real physical motion (shear, torque)so its highly unlikely that they would ever fail or fall out.
Once I set up the lathe, I was able to make 15-20 pcs per hr. Fun intended, David you must be a Tinker-er.
colin stafford

Colin,Think about the pressures involved in a brake system,
1. The force exerted by your leg/foot.
2. The leverage obtained via the brake pedal.
3. The area of the brake master piston forcing fluid into the system. You must be talking about 1000psi.

On test and at these pressures I have seen fluid leak between the sleeve and the housing bore.

Call me a Tinker-er but I believe in a belt and braces approach when it comes to safety critical components.
David Tinker

Its pretty difficult to get a good, hydraulic seal between aluminum and stainless steel, with a thermal shrink fit and no sealing compound. I have seen these sleeves leak around the closed end of the brake cylinder. Bonding in with Loctite 620 forms a high temp. bond and sealing process and is totally impervious to brake fluids. But you must have a few thousandth clearance for the bond line.
Did not work out the PSI hydraulics numbers, but its all radial against the sleeve and has nowhere to go but push the seal and piston.
colin stafford

This thread was discussed between 08/05/2001 and 17/05/2001

MG TD TF 1500 index

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