Bleeding dual circuit brakes?

[RickB]

The pedal still feels a bit soft after bleeding yesterday.
Actually it's great sometimes and a bit soft other times.
I am thinking my front circuit is great but my back circuit has air in it.

Is there anything special I have to do to get this bled properly? In particular what to do about it when you open up the bleeder & press on the pedal the front brakes engage & the pedal is firm? It doesn't seem I'm getting much action towards the back. It's been a long time since I've done this.
Thanks!

 

[tosoutherncars]

Hiya Rick,

I had a really hard time bleeding the brakes on the Midget until I bought a hand pump (see for example the Mityvac ). I find it much easier, and can now bleed the brakes without an assistant.

Good luck hunting down your air bubbles!

 

[Bugeye58]

Rick, is the hose at the rear in good shape? A hose that is deteriorated can cause restricted flow, making it hard to bleed the brakes. Not to mention severely imparing their overall operation.
Jeff

 

[RickB]

Thanks guys, yes the hoses are all great. It's really just that I don't have the right size wrench for opening the bleeder & they don't sell it at the parts store and I had to use needle nose locking pliers and etc etc etc.
Seems better now that I've done it the third time.

 

[tosoutherncars]

Rick, the bleed screws (on mine, anyway) are plain ol' 1/4". Should be easy to find...

 

[RickB]

Funny, I thought I tried a 1/4 inch and it was too big.
Also tried 6mm & it was too small while 7mm was too big.
Sounds like a 1/4 doesn't it?

 

[Gearhead]

I've had great results with a vacuum device called a Vacula you need a air compressor to "power" or drive it but all you have to do is attach it to the bleeder port open it and it will suck all the air/brake fluid for you I 've used to suck the old fluid out of the master cylinders, transmissions any thing you need to remove fluid from I still will bleed the old fashion way just to check for air once I have clean fluid coming out but it sure saves alot of time bleeding out new or old systems

 

[RickB]

In the category of "no good idea ever goes unpunished" I decided I'd go ahead and replace the fluid in the back circuit today because it looked dirty.
So I pulled off the other wheel & opened the bleeder. My assistant in place behind the wheel pushed the pedal down, up, down, up and so on. After I saw clean fluid coming out I went ahead and closed the bleeder. Except that it was leaking. I gave it a little more of a turn.

Stripped out the wheel cylinder bleeder valve hole.

Wonderful. It's a holiday, no way am I getting another wheel cylinder today. Can't drive it to work tomorrow & our van has engine problems. Sometimes you really wish you had left well enough alone.

My other cylinder isn't stripped but it was leaking. Too bad I don't have a rebuild kit.

 

[RickB]

Well I took both cylinders apart, picked out the best looking seals and cleaned it all up as good as possible then put one "good" cylinder together.

Bled both sides again & tried her out.

This will work for a while, I don't know how long but I have officially reached my quota of brake work for a while. /bcforum/images/%%GRAEMLIN_URL%%/wall.gif

 

[tosoutherncars]

Rick, as others have said, and (for once) I listened to good advice in redoing my rear axle... Don't bother trying to rebuild the cylinders. I think mine were $18 a set, or maybe that was per side. Either way, not worth trying to pull them apart, rebuild them, new gaiters, etc... toss 'em, slap in new ones, and be done with it.

I ordered my parts from Harold Rininger (see https://stores.ebay.com/Harolds-TriumphMG-Parts) who was inexpensive and quick to ship, and had bearings & wheel cylinders in stock. I'm sure that Tony, and others here, would be able to supply also.

My $0.03 (Canadian)

 

[RickB]

Thanks Duncan, the local NAPA auto parts has access to 140+ in a warehouse about 20 miles from here.
If I call them tomorrow morning they will have one for me by noon. They cost $20 US each.

I was simply not thinking I should replace both at the same time, so I only ordered one. Oh well, tomorrow morning I'll ask them to get me another & it will be ready for me when I get home from work.

"Rebuilding" the one I have simply allows me to go to work tomorrow.

It's the classic question - what do you do if you lose all the lug nuts while changing a tire? Or- what happens if you strip out the bleeder on the second side trying to bleed the brakes after you replaced the first side and you don't have a spare cylinder? Make a good one out of two bad ones.

 

[tosoutherncars]

AAAh, gotcha! Well, you know the old joke... brakes, manual trans, and a horn; any two out of the three, and you're good to go! Just don't tailgate anyone with a heavy brake foot. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[RickB]

uh - oh...
My horn isn't working! /bcforum/images/%%GRAEMLIN_URL%%/cryin.gif