7 replies to this topic

[bingo95b]

Hi All,

 

I have had this brake problem for quite a while.  When easing into a parking spot and especially when i run in reverse, i depress the brake pedal and it goes in almost all the way. When I press it again, it firms up and brakes like normal.

 

while driving in traffic (stop and go) or for long periods of time at higher speeds, the brakes seem to work fine.

 

Have tried bleeding (several times, unless there is a different way to do this, i have gotten all the air out)

 

I have an 1978 belgian mini special 1100, the front brakes have been converted to discs, and no servo with the single line (looks like a can) master cylinder.

 

Any ideas?

 

Thanks

 

 

[MrBounce]

It sounds like

 

1) There is still air in the system - did you use an eezibleed or did you & a mate do it manually?

 

2) If that's the original master cylinder it might not be fully up to the job of operating the calipers - there might not be enough fluid in the system. You need the larger one like this:

 

http://www.minispare...px|Back to shop

[bingo95b]

Me and a mate just did the bleed.  Will have at it again this weekend.

 

and yes its the original master cylinder.  If that is the case, then i will try to get a replacement soon.

 

Thanks!

[Captain Mainwaring]

I wouldn't change the master cylinder yet. When you finally get a pedal, does the car stop OK without excessive effort?

 

(it should)

 

If it does, then I'd start looking at adjustment/wheel bearings, both of which will give you that lost motion you mention (not saying air wouldn't either) but the "when reversing and making tight turns" pushes me towards adjustment and wheel bearings, with wheel bearings being first on the list.

[KernowCooper]

Assuming the pistons are not being pushed back by a slack wheel bearing then it points to the master cylinder and I'd change it.

[Captain Mainwaring]

Given the symptoms - I'd leave it and check the other potential causes first.

Of course it can't hurt to change it anyway, but it would look silly if the symptoms still persisted afterwards.

[sonikk4]

Having done this conversion i replaced the old master cylinder with the larger Cooper S version to mirror the Cooper S spec.

 

When you did the conversion did you ensure the wheel bearings were seated correctly within the hub and also the correct torque loading?? 

 

When i bled mine we did it as per Mr haynes book and an old BMC workshop manual i had. We went round the car several times before all was good. Also i changed all of the old flexi pipes for Aeroquip Stainless braided items and overhauled the rear drums and replaced the slave cylinders on both sides.

 

We used both an Easi bleed and also the old manual method as well. If you are not leaking fluid anywhere and there is no air i would have a look at the front hubs to see if everything is correct there. You may have to disassemble the hub and check out the bearings to see that they have seated correctly.

[bingo95b]

Thanks for all your help. We disassembled the hub and found that the nut with the split pin was loose and that the rod that it screwed into had lost some of its thread. A quick visit to one of the junkyards yielded a replacement and after repacking all the bearings, everything was fine.