Classic/Antique Car Repair/hydraulic brakes

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Expert: Paul Wilczynski - 12/20/2008


Question
How can I free up wheel cylinders that have been sitting for 50 years.  Of course I would like to do it without damaging any of the parts.  Cylinders are cast iron.  Pistons appear to be aluminum.  When I removed the cylinder a small amount of still-liquid brake fluid drained out.

Answer
Hi, Eric!

You don't mention what type of car, so Ill keep my answer general.

This may not be possible to do without damaging the parts. The alloy pistons will have corroded and the cylinders are probably rusted from water in the fluid; brake fluid does absorb and hold a lot of water in this long a time.

Here's how I do this: I remove the rubber cups and the show retainers and any other clips and hardware, until the piston backs are exposed. Sounds like you've done this already.

Next step is to secure the cylinder in a bench vise with soft jaws. Orient the cylinder vertically and use a thick drift or piece or rebar or steel rod at least 1/2" in diameter, and a 2-pound ball pein hammer. A few good whacks will often be the only thing needed. On the other hand, you may end up cracking or distorting the pistons before they finally shift.

If this fails to work, you'll have to do the machine shop thing. They will try to press the pistons out, and failing this, will bore them out.

Next, if the wheel cylinders are badly pitted from rust, they can often be bored oversize and sleeved, or bored oversize and new oversize pistons fitted. This can change the brakes' feel, requiring more pedal pressure, though.

Pistons can be turned out of aluminum stock to fit the rebored cylinder.

This is pretty standard automotive machine shop stuff. If you can;t get it done locally, check with Hemmings online, under "Services Offered" for vendors who offer this service.

--Paul  

Classic/Antique Car Repair

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Paul Wilczynski

Expertise

Most questions involving vintage car restoration, mechanical and body, paint and upholstery. Parts sourcing. Extensive experience in wood-bodied station wagons, British and French cars of the '40s through '70s. Rolls-Royce Silver Shadow, Sunbeam Alpine and Tiger, Citroen Maserati, VW Beetle, 1955-65 Chevrolet (especially Nomad station wagons), Corvair.

Experience

Wide-ranging and long-term. I owned a restoration shop in the 1970s, continue to dabble in vintage exotics. At one time, had a seven-car collection of contemporary exotics which I had restored and maintained myself. When I was 18 years old, I designed a woodie kit for the VW Beetle, which I developed into a product which was featured on television and in over 100 magazines and 25 books at last count. I still own and drive one of my creations. I owned a design and fabrication consultancy from 1982-2002, specializing in show car fabrication for manufacturers including Ford, Mazda, GM, Subaru, Mitsubishi, etc. Since 2003, I have been a department manager in Industrial Design, and a full-time instructor in automotive design and fabrication at the university level. My students go on to design automobiles as staff designers for major auto manufacturers worldwide.

Organizations
Western Automotive Journalists, Industrial Design Society of America.

Publications
Long list of magazines and books, including Playboy, VW Trends, VW Greats, Hot VWs, and European automotive magazines.

Education/Credentials
I teach design and fabrication at university level. My education is in Industrial Design, University of Illinois (1966-1970).

Awards and Honors
Many awards for restorations in local concours and shows.

Past/Present Clients
Mazda, Ford, GM, Subaru, Mitsubishi, Honda, Toyota, Chrysler, Mercedes, Porsche.

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