Practically Classics Forum

Hi , decided to take the jag out for a run today, started fine and pulled out of the workshop ok . When I applied the brakes found the pedal harder than usual then when I tried to pull away the brakes were on solid and the pedal was very high and wouldn't push down at all . Pulling on the pedal released the brakes a bit but not much. All the brake system was new about 200 miles back, new servo, master cylinder , pipes etc. Any idea where to start looking would be very grateful , Thanks

t souds like a master cylinder or servo fault, if it were further down the line the pedal would still be working and only one or two brakes would be stuck, so I would start by loosening the master cylinder union and seeing if that releases the system pressure. Just because things are new it doesn;t mean they work properly, witness the rubbish available in Lucas boxes these days!

I had the same problem with my little used P6 Rover - That also had a new master cylinder (Lucas) that had done little work - but for some reason the piston was not returning - I took it apart and rebuilt it but it was the same within a month - in the end I threw it out and replaced it - I agree with Mr Rusty there is some rubbish parts on the market and in some cases brand names appear not to warrent that you are fitting a quaility part.

As above, sounds like the master cylinder is faulty and not letting the piston fully return. This may be for some external reason, you should be able to check this, but sadly it may indeed be a rubbish quality aftermarket part - I hope you still have the receipt and can get your money back if this turns out to be the case?

Do you still have the original master cylinder? If you do, I'd recommend getting this refurbished (stainless steel sleeves are a good idea) as it'll probably be a far better proposition than a new one.

All the best with it!

Thanks for the advice, I will check that first. All the parts are from david manners so I thought they were all good quality . All 4 wheels are braked and the brake lights are permenantly on.

Cheers Chris

The brake lights on confirms the diagnosis of master cylinder or servo because they are operated by hydraulic pressure. If it is a remote servo, then also check the air valve. You could try slackening the unions on the outlet of the master cylinder and the outlet of the servo, which should give you a clearer indication of where the fault lies.

When I rebuilt the brakes on my ex-Riley 1.5, I fitted a remote servo and had exactly your problem. Undoing the air valve allowed the system to equalize and had no problems after that.

Thanks for the help, I cracked the joint on the mastercylinder and the brakes instantly released , so I think this confirms it to be the problem. I'll get a new one ordered .

Cheers Chris