Healey Master Cylinder Clevis Pins

When the workers on the BMC assembly lines assembled Austin Healeys I’m sure they were told time and time again to put a dab of grease on the master cylinder clevis pins before installing them. These are the little 5/16″ diameter pins which form the attachment between the pedals and the brake and clutch master cylinder push rods.
Probably, when the “governor” was looking these little items were dutifully coated with some sort of grease however, most of the time, they were slipped into place without so much as a sniff of lubricant of any sort.

The sad fact is that it takes longer than the warranty period for something like this to wear out to the point where it is noticeable so I’m betting that the practice continued unchecked throughout the 15 years of Healey assembly.

The result is that after a considerable mileage these un-lubricated pins get badly worn.
These are a couple of examples that I removed from Healeys over the years.

clevis-pins.jpg

Unlike modern cars the braking systems in Healeys, and for that matter most cars built before 1968, were designed with no duplication meaning that if one brake component failed the entire system failed. After 1968 all North American market cars had to have  “tandem” braking systems but, interestingly, this duplication does not include this little item, so failure of this pin can still cause total brake failure.

Another interesting thing about brake systems is that for the most part they are used very gently; after all vigorous application of the brakes usually makes passengers nervous. The only time that brakes are applied hard is during a “panic” stop and that, of course, is when components are subjected to the greatest loads and failure produces the most serious consequences.

I’m constantly amazed that I have never heard of an accident having been caused by brake failure attributable to the shearing of one of these pins. I’m sure that there are plenty of MGB’s and Healeys and Triumphs running around, all of which use the same system, with pins as worn as much or even more than those shown here.

If you drive a high mileage British Sportscar this winter may be a good time to check these out.

About Michael

Who is this guy? Born in New Zealand some time back. Went to Maori Hill Primary School then Kaikorai Valley High before joining the RNZAF and an Airman Cadet in 1968. Graduated 1972 with an NZCE in Aeronautical Engineering. Then embarked on the typical Kiwis "Big Trip Overseas". Got to see quite a few places, and spent a while in the U.K. "home" as it was refered to by many New Zealanders in those days, before travelling on to New York and then to Canada by bus!! This trip is presently on hold (has been for the last 34 years). Met my dear wife Judy not long after arriving in Ontario and we have been happily married since 1976. After travelling around New Zealand and the pacific in 1979 I started Precision Sportscar andfor the next 23 years grew the business and helped raise 2 boys Drew and Robin.
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3 Responses to Healey Master Cylinder Clevis Pins

  1. Alan says:

    Micheal –

    Those pictures brought back some memories!!

    When I took apart my BJ8 20 years ago, all of the clevis pins looked like that. In fact it was worse because the brake clevis was so worn the pin had completely offset … so not only was it worn where the fork is, it was also worn on the frontside where the pedal pushed on the pin… the pin was shaped like a little minature crankshaft.

    Because of this pin, the brake action when I stepped on the pedal was very very sloppy, and sometimes the pedal just clunked down like it was broken – when in fact it was the offset clevis pin rotating around in the hole like a crankshaft. Glad I fixed it!

    Cheers,

    Alan

  2. Steve Gerow says:

    I like the fact that Pegasusautoracing.com sells genuine Girling master cylinders with screw-on clevises (clevi?). These are much heaver than the sheet metal welded-on clevises that come on the OEM cylinders. These cylinders are mostly cheaper than those sold as OEM.

    Here in Pasadena, CA we’re lucky enough to have a local industrial hardware store that sells almost everything, including clevises and oil coolers.

    I used cut-down plain-shank 5/16″ bolts for replacement clevis pins because I was too cheap to buy the clevis pins.

  3. Robert Beauchemin says:

    Mike , as Steve said I too use cutdown 5/16″ bolts but I go further as the problem I feel starts with too little surface area on the clevis.I silver solder 2 thickwashers on the side of the clevis and then run a reamer through the hole for an exact fit. I also apply a layer of EP lubricant on the bolt for extended life. Works a treat for me.

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