HELP THE MAROON ENGINEER APPRENTICE

[guydenning]

here we go. further reinforcement of my legendary crap mechanical skills...
the brakes have gone on holiday. the pedal hits the metal and no slowing of vehicle occurs - which isn't good (even i know that). i had a look at the hubs and there seemed to be leekage of something on one rear tyre, so off came the wheel and hub etc...
inside there was a lot of black cak (brake lining stuff all congealed - suggesting some fluid was getting in there congealing it!) good aren't i...
had trouble figuring out how to get the pads off and (don't laugh) ended up removing the axle inner shaft (long isn't it) - eventually got that back in with much wiggling, and figured out the voodoo pad spring mechanism. the brake cylinder came apart (i assume it's the piston) and the whole mechanism is not fixed to the plate. firstly is this cylinder meant to 'float' - in my simple mind it would seem the right thing but i like to check... secondly is the piston meant to drop out?
tomorrow i will mostly be getting oily again. seeing everything's covered in fluid, oil from the prop, and associated other cak it's a bit difficult to know where the fault may lie. what's the accepted plan of attack... answers on a postcard please.

i thankyou

[rayofleamington]

had trouble figuring out how to get the pads off

no wonder, as it doesn't have pads!!!! (pads go on disks and you don't appear to have rear disks...)
Anyway - I'm glad you worked out how to get the shoes and springs off. ;-)

The brake cylinder is meant to float as it has a single piston - therefore as the piston moves and pushes one shoe, the opposing force causes the cylinder to slide and push the other shoe.

The piston is in 2 parts - the outer part is meant to drop out. The inner part won't come out unless you remove the handbrake actuation lever.

Before you strip the cylider off / apart, ake sure there is plenty of fluid in the reservoir. If not, fill it up! Then pump the brakes to see where the fluid is leaking - you should see a lot of fluid if the pedal goes to the floor (unless the pedal travel was caused by lack of fluid in the first place).

[guydenning]

something's not right because the fluid was only topped up a week ago. and there was no gradual deterioration - it just went from 'brakes available captain' to 'oh ho ho - i don't think so matey'.
right then - overalls on - always happens on a bank holiday doesn't it...

[bigginger]

'swhat happened with mine. On stripdown (of the brakes...) found that one wheel cylinder had exploded - the piston had poppped out of the bore. I guessed it was just that the seals had deteriorated. I fitted discs (!) but you can't do that at the back, so new wheel cylinders and shoes, and you may as well do the flexi hoses while you're at it. G'luck

[guydenning]

well i removed the master cylinder too - i love torsion bars i do - f%#*$ng things. fitted a new seal fixit pack, spent an hour and a half bleeding the back brakes, then it got too dark to see. back out this morning then - let's see if there's any pressure at all to the system! otherwise it's charlie wares on monday with a load of cash stuffed in a happy shopper bag... and a blue mog convertible drove past without stopping to offer their assistance. people today eh?

[Matt]

Did the M/C have any fluid in it? if not you have sprung a leak somewhere. It happened to me, the pipe running from the M/C Bango to the 3 way union thing at the front was rubbing on a chassis leg and rubbed through! do'h. You could have axle oil in the rear brakes causing the gungy effect (happened to me too). And as you have already removed the half shaft (the "axle inner shaft") and know how easy it is you should probably replace the seal. (it might or might not have a rubber o ring....)

[guydenning]

i think it's a combination of a shot rear cylinder (the rubber looked like it was whittle out of plasticine by a five year old with a spoon) and a dodgy master cylinder. Now that fifi's in so many pieces i think it would be a bit daft to just fit repair kits. i'm feeling particularly oily and confident so i'm going to replace the whole braking system, copper and all. any potential surprises out there from those that have one this (please no more surprises like the torsion bar - that was a rare old treat of a job)

[Rasputin]

What was so difficult about the torsion bar? You only have to lever it out of the way to get at the master cylinder bolts.

[bmcecosse]

Don't use COPPER for brake pipes ! It should be KUNIFER - or good old BUNDY tubing.

[Onne]

And if you replace all of it, use silicone(?) brake fluid.

Onne

[bigginger]

...and could you tell me if you find somewhere that sells P clips for securing the pipe? Modern regs are, I believe that it should be supported every 30 cm, BTW.

[Onne]

Are they hard to get hold of then? I think we sell em..... I'll ask tomorrow

[bigginger]

Not tried beyond Halfords yet, but all the car shops around here are the front spoiler and fake big exhaust extensions type, so if Guy finds somewhere in Bristol or Bath...

[guydenning]

i don't know if it's the meet tonight - but if it is and we do turn up it'll be on Matt the Black bike - on the line front, are the regs retrospective? and how neccesary are they? the thirty cm rule rings familiar though with a kit car programme i caught ages ago...

[bigginger]

I don't know if they're retrospective - saw it on a kit car prog too! I do know I want to secure my pipes a bit better though. Yep, I'm assuming it's the meet tonight.
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