50 replies to this topic

[Spider]

I know some of the other guys have already suggested it, but if the brakes are all adjusted up (and don't forget there are two adjusters on each front wheel - so 6 for the whole car), it's bled and it's not externally leaking anywhere, it has to be the Master Cylinder.

 

Just on the adjusters, the fronts are on a 'cam' so they only need very small movements for adjustment, usually about 1/8th of a turn, the rears are on a screw, so may need a few full turns.

[garysmoc]

Thanks Moke Spider. I think the chances of 2 defective genuine ap master cylinders is pretty unlikely. I still think the issue is the fact the replacement master cylinder is nothing like the original as these have been our of production since 1981.

[Dr s]

Have you replaced the Flexis yet? I wonder if one of them is ballooning?

[garysmoc]

Not replaced them yet. They look and feel fine and good flow through them. They don't appear to be breaking down either

[KernowCooper]

You did mention somewhere ? you saw bits of black floaters in the fluid ? master cylinders are new so only leaves the flexys. have you done what we used to do, clamp each flexy hose off close to the entry point and then retry the pedal

Edited by KernowCooper, 21 July 2015 - 08:05 PM.

[garysmoc]

The black floaters were in just one cylinder, so that flesh may be slight breaking down. Every one was clamped off individually and it made no difference to pedal.

[minidaves]

ok pain in the butt, but 1st question what fluid are you using? and i would start with some bleed nipples on bits of the system the bais valve can cause this for sure, so i would get two metric inline connectors and join the brake pipes either side of the valve.  and start from there,  it also means u can put 2 bleed nipples at this point and check the cylinder, and then connect and check each circuit. and another thought are the pipes connected the right way?  

[garysmoc]

Dot 4 fluid. We have bled master cylinder and all the bias valve unions while pressurised by the easibleed at 20 psi. I am absolutely sure the system is free of air. We have put a block valve where the rears split to cut those off and check fronts. When I bought car the cylinder was plumbed in reverse so back brakes did all the work. This has been corrected. Having found house sensitive the front adjusters are and the fact the brakes are so sharp with just millimetres of travel when you reach the biting point, my mini garage is going to have a further go at them. At least I can drive it there now.

[garysmoc]

After further checks by me and my mini garage, it appears that the front wheel adjusters are Infact quite loose on one adjuster each side. As a result they gradually undo when you brake until front brakes don't work at all and just the rears are doing the work, which because of the splitter reduces the pressure a lot and the car barely stops, which is why pumping brakes stops car, because the rears are given another boost of fluid. If you adjust them until binding the pedal comes back up to near the top and by driving each time you brake they get gradually worse. Given these are brand new mini sport back plates, pre-assembled with shoes and cylinders, I am guessing the come this way. Has anyone else experienced this and is there anyway of tightening the front adjusters. I think once they have got dirty, dusty and rusty the problem will go away.

[Mini Manannán]

mini sport 

 

[garysmoc]

I now finally have the problem solved. The brand new front back plates adjusters have become so,loose they can be turned by hand. They consequently unadjust each time you press pedal. Having done just 2 journeys and 200 miles this shouldn't have been possible. I have sourced and fitted a different make of front backplate and fingers crossed it will work. I can't believe the money I have wasted on new parts I didn't need. I know now this mini should have the best brakes around as it is all new!

[garysmoc]

Having driven the car today, the new back plates have managed to work the adjusters loose and they are now as bad as the last new set. Am I doing something wrong as they were tight and adjusted to binding slightly and after just a few miles, the adjusters had become loose at back plate and the back brakes were all,that was working. My mini garage says they are defectively manufactured and not enough shims on backplate adjuster. Are they correct and what can I do?

[sledgehammer]

I've got no suggestions for that - parts need returning / reporting 

 

sounds like it was the paint holding them in place

 

also have you tried adjusting the opposite way - to stop the shoe returning too far ? (hard to describe)

 

as it's brakes you can't really compromise on safety

 

I take it , that they are swaged in place , so can't be removed / fit extra shim / thrust washer ?

 

It's been years since I worked on front drums - thought they had a circlip

Edited by sledgehammer, 05 September 2015 - 10:55 AM.

[Spider]

As you no doubt know, the adjusters here will turn through full adjustment over 180⁰ and can do a full 360⁰ turn from full slack, to full adjustment and back again. It's likely you know and your garage too, but the adjusters are supposed to be turned to take up the adjustment in the same direction as the wheel turns. None the less, if they are not corrected fitted / made, then this will make no difference.

 

There are (were?) replacement adjusters available, they are after-market, there were none from the factory (that I am aware of at least). Maybe hunt up a set of them and see how you go.

Edited by Moke Spider, 05 September 2015 - 11:27 AM.

[Spider]

Here's a set of fitting instructions

 

http://www.paddocksp...for_RTC3176.pdf

 

and this is what the kit for a mini looked like

 

http://www.minimania...ment-Repair-Kit

 

they seem a little hard to come by these days but appears they do come up often on ebay