Classic/Antique Car Repair/1979 MGB Brakes

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Expert: Paul Wilczynski - 4/21/2009


Question
Braking switches unpredictably between all four wheel brakes grabbing with normal brake pedal travel, to only front wheels grabbing and very hard brake pedal actuation.  May go one way for an hour, then the other way for an hour, no obvious reason for change.  Could this be possible brake master cylinder seal problem or could it be related to the pressure differential switch?  Thanks in advance for any guidance you can offer.

Answer
When was the last time the brakes were gone through really thoroughly?

The master cylinder is immediately suspect, but if it's not being driven a whole lot (and what MGB ever is?), you're going to have to look at the calipers and wheel cylinders on the rear, too. The proportioning valve is a fairly simple device, but water or moisture in the lines can ruin any or all of these components.

Check, in this order:

Master cylinder

Calipers

Rear Wheel cylinders

Proportioning valve

Front flex lines (they often swell shut with time)

All of these components shoulds be in prime condition if you want your MGB to stop safely like a mod'n automobile!

--Paul

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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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