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MG MGA - How bad are the blue caliper pistons?

Hi all,
I ordered MGB caliper pistons from Jeff Zorn for the MGA. As luck would have it I ended up with the blue steel ones. Jeff says Moss had problems with the stainless ones and no longer carries them. He didn't mention the chrome I asked about so I am going to assume these are not available too. Has anyone had the steel ones in for a lengh of time. Do they rust as mentioned they could in the archives? Jeff also mentioned he has a source for stainless at $37.50 each....ouch.....that's a little hefty on the brake budget. Any info appreciated.
Thanks John
John Cline

John,
I haven't tried the stainless, but at #37.50, I would say that they are very reasonable.
mike parker

Let's see...if I buy the steel ones and they rust, it will then eat up the caliper seals and I lose my brakes. I now have a piece of junk for a car because it is now wreaked. Or I can spend $37.50x4 for a total of $150.00. I now will have excellent brakes and a car that is not junk. I almost forgot...the car with the cheap calipers will be junk ..and I bet the driver will be too!!!. The two things I never go CHEAP on is anything made to stop the car and anything which will control the steering..tires,rims, hubs ect. What is your life worth?
JEFF BECKER

Jeff, I see your point about going cheap on safety items. But if these are selling as a standard item from Moss and it seems the are the only ones they carry are they unsafe? What I am wondering have they failed for anyone using them for a length of time? At this point I do plan on returning them and start searching for chrome.
John Cline

John- I had the same trouble in 03 when I redid mine. I did not want those blue steel ones and ended up finding some at Proper MG. I just googled them and found they are under new owners and closed at this time. What ever you do they will be cheaper than the original kind. I used several used ones and a new one when I restored mine,17 yrs later they rusted bad, so I converted to the MGB type.
gary starr

Try Scarbofaire and see what they have and price.
JEFF BECKER

John. I received some caliper pistons, which seemed to be carbon steel with a black oxide finish, from Moss several years ago. Moss was unable to tell me whether the pistons were carbon steel with black oxide, stainless steel with chrome sulfide (which will blacken some forms of stainless), or anything else about the pistons.

Industrial black oxide (bluing, blueing) is done by cleaning the carbon steel parts throughly in a heated solution of lye, then, boiling them in the bluing solution for about 20 minutes at 275-305 deg F. This causes a change in the surface of the metal to a depth of about .002". The resulting finish is not rust resistant to any great extent. Hardness of the material and the degree of polish also affect the speed at which a part will rust. The harder part will rust more slowly than the softer part and the more highly polished part will rust more slowly than the less highly polished part. But, all forms of carbon steel will rust if exposed to water and air. If there is salt present, the rusting is accelerated significantly. A single grain of table salt, in a high humidity environment, can, when in direct contact with stainless steel, cause it to begin to rust.

Hence, some form of plating, applied to carbon steel pistons, is probably the best. Second best would be to use pistons made of stainless steel. Pistons of carbon steel, regardless of whether they are blued or not, increase the possibility of rust developing on the piston with possible damage to the piston seals as a result.

Until I can get some accurate information concerning the material used to make the current "blued pistons", I will neither use them myself, nor, will I recommend them to anyone else.

We have all written, over the years, complaining of cheap parts. This seems to be an example of one. When I received them, I sent them back and Moss found sufficient chrome plated parts for my needs. Were I forced to use these parts to keep a car on the road, I would take them to a professional plating operation and have a coating of electroless nickel applied to prevent rusting. However, to have only four pistons done would cost about the price of the stainless ones Mike has mentioned.

Les

Les Bengtson

Here's a source for stainless pistons. His name is John Farrell and his speciality is Jaguars. However, he also makes some parts for the MGA. His quality is better than NOS.

Don


http://www.fortunecity.com/silverstone/tread/1046/id23.htm
Don Tremblay

Thanks all for all the info. Les, I see what your saying that no matter how the steel is treated it will still rust if not plated. Don, Thanks for the link to the John Farrell site. I'm suprised he has actual MGA caliper pistons for only $5.00 more than the MGB. Looks like I'll be going in that direction.
John Cline

There are anodised aluminum pistons starting to appear, too. Don't know if they're available for the MGA. The ones for a TR were seen at BPNW.
Tom

Tom,
I checked out the British Parts Northwest site and found they do have MGB pistons. They say the are Plasma Nitrated, what ever that is and it last as long as stainless steel at half the price. Not sure what to think of that.
John Cline

I too ordered the blue pistons and was disappointed. Cost was 50 USD for 4. P/N 180-745
Returned and replaced with Lockheed stainless, P/N 180-748 Cost was75 USD. From LBC.
Art

I have emailed the guys at BPNW and received timely, helpful answers. If you have any questions about their parts, they seem to know the answers from experience.

I like the look of nice smooth chromed pistons, too. But all it takes is a little nick and some moisture, and they rust/flake, too.
Tom

John in Wisconsin... (I wish you had shown your email address) You'll find that the SS psitons will not include the slug for the center pin, and that you'll have to remove and reuse your old one. Difficult. The more reasonable solution is to use MGB pistons, and remove the pin from the caliper body. Easily done, and the pin thing is useless and redundant. Peter C. (also in WI)
Peter Caldwell

Peter sorry didn't check the right box on the e-mail thing. I havn't order them yet but after reading the archives it looks that using the MGB pistons might eliminate potential binding. Where you at in Wisconsin. Right now I have most of the chassis work done, the body has had the paint removed and I've primered the all the inner stuff like the engine bay trunk etc. Ran out of warm weather to do much with exterior finishing but springs got to get her sooner or later.
John Cline

John. Peter owns World Wide Auto Parts, known for their high quality of shock absorber (hydraulic dampener) rebuilds. His business is located in Madison. I only mention this because Peter is one of those gentleman who will not use this forum to advertise his own business. His rebuilt shocks are performing well on my 68 GT and have been for a number of years now. His company is also the source for the drop in distributor bushings for the Lucas distributor which were mentioned in my tech article on the subject.

Les
Les Bengtson

This thread was discussed between 28/11/2006 and 02/12/2006

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