O/S/F wheel intermittent braking without pedal being depressed around 70 mph

[lycoming]

Problem solved .After very close inpection of the caliper once removed the piston travel was smooth and constant easy to push back in in the normal manner once it was fully seated it protruded from the cylender 1/8th of an inch ,matching this to a new one which sat flush the protrution was enough to cause the inner brake pad to touch the disc causing the disc to heat and expand just enough for it to grab thus generating more heat and increasing braking on that disc .New caliper and pads ,as good as new now.
Thanks Steve and all the guys

 

[mattkh]

Well done.
You say it happened once you reached 70. How many minutes was it taking you to get to that speed? As you say that is how long it was taking the disc to warm up and expand to cause the problem.

One more thing. Any idea why it was protruding 1/8th of an inch?

 

[EmilysDad]

.....
One more thing. Any idea why it was protruding 1/8th of an inch?

I thought that too. Was the piston 1/8" too long or just not going into the bore by an eighth?

 

[onefortheroad]

Lie coming.... mmmmm . I wonder

 

[Kev555]

I had seen a post similar a while back on the forum here with a vehicle having the same issue of automatically braking on one side at speed. Cant remember if the issue was found.

 

[lycoming]

Lie coming.... mmmmm . I wonder

Strange comment from a senior mrb ?

Well done.
You say it happened once you reached 70. How many minutes was it taking you to get to that speed? As you say that is how long it was taking the disc to warm up and expand to cause the problem.

One more thing. Any idea why it was protruding 1/8th of an inch?

there was a ring of corosion under the gaytor

 

[lycoming]

I thought that too. Was the piston 1/8" too long or just not going into the bore by an eighth?

correct length just corrosion

 

[lycoming]

Well done.
You say it happened once you reached 70. How many minutes was it taking you to get to that speed? As you say that is how long it was taking the disc to warm up and expand to cause the problem.

One more thing. Any idea why it was protruding 1/8th of an inch?

corosion was the cause

 

[EmilysDad]

correct length just corrosion

I thought so

 

[Botus]

Problem solved .After very close inpection of the caliper once removed the piston travel was smooth and constant easy to push back in in the normal manner once it was fully seated it protruded from the cylender 1/8th of an inch ,matching this to a new one which sat flush the protrution was enough to cause the inner brake pad to touch the disc causing the disc to heat and expand just enough for it to grab thus generating more heat and increasing braking on that disc .New caliper and pads ,as good as new now.
Thanks Steve and all the guys

brake calipers having strange behaviour is now very common..... since circa 1995 the odd caliper replacement to cure weird braking faults is "normal"

quite "an interesting design feature" as they are some of the most simple mechanical / hydraulic things on a vehicle.... and in stark contrast to how you could have an older car that never had a fluid change, never had anything other than shoes or pads in 25 years and nothing ever played up