Car is a fully restored 1964 E-type roadster...bone stock. Took the car out today for a drive and something with the brakes didn't feel quite right. When I got home I measured my disc temperatures...the fronts were a cool 95 degrees (by the time I found my IR thermometer), but the rears were a very toasty 410 degrees! Seems like the rear brakes are dragging. Where to I start in diagnosing what's wrong?

Many thanks in advance,
Alan
Fair Haven, NJ

 

I think I've figured this out...I looked at the master cylinder feeding the rear brakes and everything appeared normal, that is until I grabbed the push-rod...it was very loose and jiggly, which tells me that the plunger in the MC did not retract fully (which would have put a compression load on the push-rod and stopped it from flopping about). Failure of the plunger to retract would, of course, put hydraulic pressure on the rear pads causing them to drag and heat up. I will now order a new MC from XK's Unlimited for a reasonable $114 or so.

 

You might check the condition of the brake hoses, while at it. Also, might want to consider have the cylinder relined with a non-corrosive liner. Years ago, I had my calipers, master and slave cylinders re-lined. But then, getting the old girl out on a regular basis is a big help in keeping her ready to run.

 

I finally got around to replacing the master cylinder with a new unit from XK's Unlimited, bled all the brakes...problem solved!

Thanks,
Alan
NJ