Powertune servo

[alfadave]

In September last year,I bought a Powertune RLE 10117 servo from mgservicesheathrow ,via ebay.

This was part of a parts package for a restoration of my '68 plus 2.

Having got the car back running last month,I found the brakes felt odd on the road.....spongy feel on first press,followed by harsh braking on second press.

After a lot of head scratching,I have, with specialist help,
discovered the source of the problem.

On dismantling the air control valve assembly,mounted on the side of the servo body,the last item to come out is a plunger with a rubber O ring approx 1/4" diameter on it.

The existing O ring was too big, causing the plunger to stick in the bore.This affected the proper operation of the servo.

The O ring was replaced with a correct sized smaller one,and all is now ok.

I did contact the ebay seller, mgservicesheathrow, and he responded that he had sold many of these servos,and had not had this problem reported.

Hope this is useful to someone?

Dave

[nigelrbfurness]

Well your supplier might not have known, but the problem with the air valve assembly has been widely encountered with the Powertune servo, if its one manufactured in India. Sometimes the air valve isn't fitted, or fitted upside down, or incorrectly assembled. I've had several of these from Moss and other suppliers and fitted them to Spridgets and MGBs as well as Elans. The instructions include some notes on assembling the air valve, implying that the purchaser is supposed to fit this assembly. I don 't think I've heard of the wrong size 'O' ring before though, so I'll add that one to the memory bank! Thanks for posting it. Its also important, by the way, to observe the rules about the angle of the body because it makes it impossible to bleed it properly if you mount it horizontally, for some reason. That caught me out on one installation.

Nigel F.

[alfadave]

Nigel,

thanks for your reply.

My Powertune servo was clearly marked " made in Taiwan" on the box.

And,yes I did note the instructions on mounting it at the correct angle.

The brakes are operating as they should now, but I must admit that if I could wind the clock back, I would have paid a bit more, and bought a reconditioned Lockheed one.

Dave