new master cylinder fitted at garage and now :(

[sarnian]

Hello all, Problem with my 1968 morris minor, decided to get the garage to fit a new master cylinder.
it came back with a solid brake pedal, abit odd i thought, after a few miles , my wife rang to complain it was like it was being restrained when driven.. yes binding , the garage had fitted the cylinder , but not slacked off any of the adjusters , so i slacked them off till all wheels span freely.
fixed it ?... not !
pressure seems to "up" itself after an hour driving, so i replaced the front cylinders and the hoses in case it was
that .. fixed it ? .. not
An hour or so driving , and .. you guessed it .. Binding.
phoned a mechanic here very knowledgable in all things morris, i explained the solid pedal .. he said have you tried adjusting
the adjustable rod attached to the mastercylinder to the brake pedal ?... ( sigh ) didnt know it existed
Fixed it ? ... Not .. ok getting peeved here.....

my question is .. Is there a sweet spot on the adjustable master cylinder arm for brake pressure , as it seems to me, there
is A. no pressure .. B. too much pressure ... C. seems to be correct then .. and hour later binding again .. CRY.
Any advise would be Greatly appreciated.
charlie

[Declan_Burns]

You cannot outrule a dud M/C. We have had two issues recently with brand new master cylinders.
Regards
Declan

[Trickydicky]

There should be 3/4" free movement at the top of the pedal before the adjustable rod starts to push against the master cylinder.
Its worth checking this first.

Richard

[minor65]

The pushrod going into the master cylinder is probably adjusted up to much, i.e not enough free play at brake pedal.

[mike.perry]

Make sure that the handbrake cables are slackened off before adjusting the brakes, then adjust them last.

[bmcecosse]

The master cylinder does need to be able to return to base - so there must be free play. Otherwise - take it back and tell them to fix it! It must be a faulty mastercylinder. The cylinder is designed to generate a small backpressure - to hold the shoes 'near' the drums so the pedal action is shorter. You should notice a rather 'long' pedal first push in the morning - or any time the brakes have not been used for a few hours. Otherwise -it should be nice and firm with just a short free play.

[brucek]

Take it back anyway - might as well let them fix it in a warm workshop rather than you try on a cold driveway! Just cos it's old doesn't mean they shouldn't do a proper job.

[sarnian]

Hello, and thank you for all the advice guys, i slackened off the handbrake cables, re adjusted all the wheel ratchets,
adjusted the bar from the Master cylinder, re tweaked it, and now they seem to be behaving.
put in a new water pump today, thermostat housing next, i think this one HAS been in the car since 1968
its crumbling where the hose attaches.
Happy motoring all.. charlie

[bmcecosse]

When fitting the new stat cover - run a drill bit through the 3 holes to open them up a bit - and cover the studs with lashings of grease !

[ronnie]

hi , the problem you describe with the master cylinder is exactly the same as the one when i bought my moggy, constantly binding brakes regardless of constant adjustment .It ended up to be the adjustment rod on the master cylinder screwed up to tight

[sarnian]

Hi, was exactly that Ronnie.. Bloney Garages eh