Hi all --

Recently I installed a set of KAD 4-pot front brakes on my '73 Mini (I have what the Haynes manual says is a type-1 tandem master cylinder). With the help of a friend I was able to bleed the brakes enough for them to work but with a spongy pedal. Also, only the outside pistons of the front brakes seem to move.

Today I decided to re-bleed the brakes. After I attempted the first bleeder of one of the front brakes, I no longer have _any_ pedal. I've spent the last 2 hours attempting to bleed the air out of the system, but with absolutely no success - I bled each corner 4 times, and still no pedal. Also, I can't get any fluid out of any corner except the right-rear. Weird. I had my wife play pedal duty for a short time, but the pedal doesn't seem to produce _any_ brake pressure at all, so I reverted back to the MityVac. Is it possible that the MC decided to stop working at the very moment that I tried to bleed my brakes? Seems unlikely.

Anyway, I would like to hear suggestions on the procedure for bleeding brakes on a Mini with a split brake system. The procedure in the Haynes manual doesn't seem to work for me.

Thanks in advance,
Jeff

 

if you pull fluid with the vac then I'd be thinking a blown seal in the master system sounds likely.

I've the type 4 with a vac servo & Cooper S disks but the Haynes procedure has always worked fine 4 me.

First time I futzed with the brakes a rear cylinder blew a seal tho ... sometimes you don't know how far on the edge you've been hanging until you ever so slightly probe a piece of the system

 

So what you're saying is that I _shouldn't_ get fluid out of the lines when I'm using a vacuum pump to bleed the brakes?

I disconnected the front brake line fitting at the master cylinder, stuck my finger over the hole and pumped the pedal. Basically, very little pressure is created. Sometimes the pressure is enough to push past the pressure I'm exerting on the hole, but most of the time it's not. I'm no expert with master cylinders (obviously) but I would expect more pressure to be created. The rear fitting behaves the same way as the front.

Since my post I pulled my MC to look at it on the bench. It's in pretty rough shape. It isn't visibly leaking out the bottom, but it's got a lot of rust. My guess is I'll be replacing it.

Thanks for the help,
Jeff

 

I'm saying there are two ways to get fluid out of the system

you can push from the top via the pedal or a special tool that applies PSI from the top

or

you can pull it from the wheels, usually from a VAC tool; but in theory from gravity.

If the vac tool pulls and the pedal does not push .... hmmmm the standard system seems bad.

If the vac can't pull I'd have to suspect a blockage

If pumping the pedal produces nothing at any wheel I suspect a main cylinder replacement or rebuild is in order (I'd replace). With a BOO KOO flush cuz I thinks you gots some swimmers in there too.

 

Yeah, MC seems to be kaput. I pulled it and have it in my vice ... it's not visibly leaking but it is rusty. I found out it's no longer available, so I have to buy a tandem MC from a newer Mini and retrofit it. Hopefully when I get it installed the brake bleeding will be a breeze ...

Jeff

 

FYI, replacing the master cylinder fixed the problem. The old style tandem master cylinder is no longer available, so I had to make some new lines to account for the change from SAE to metric fittings. I bled the system with the new master cylinder and everything works a champ!

Cheers,
Jeff

 

never say everything works...

you tempt the gods to mess something up!

get some good driving days in while you can!

 

As of right now ... it's 101 degF and it's 3pm. Not many good driving days left until September.

Jeff

 

To bleed the system start with the L/H rear, R/H rear, L/H front, R/h frontand use an ezeebleed kitthis is a 1 man bleeding system............

http://www.minispares.com/Product.aspx?ty=pb&pid=33522

 

Would this be different for LHD minis? My understanding is bleed the one furthest away from the MC is first...

 

You are correct. Start on a LH drive car at the RR.

 

sorry I forgot your LHanded...........Use the easy bleed kit as this pushes all the air out of the system without the use of the pedel squishing the fluid.....allways works fine for me...........

 

So ive read! I just need to find a local place that sells em. Or even a place online. I wanna do it this weekend but I dont know if i will have the chance to.

 

Summit Racing (www.summitracing.com) sells the power bleeders. I used it when bleeding the new brake system on my Mini and it _really_ takes the pain out of bleeding brakes (and clutches).

Jeff

 

Thanks! I found some on ebay as well!