Adjusting pedal height after brake rebuild

[54woody]

When I got my car it had non-functioning brakes. I've replaced the front shoes, the master, and all wheel cylinders and have been struggling all week trying to bleed the system. I used an eezibleed. After going round the vehicle 3 times on three separate days, the pedal was still going to the floor. I found some minor sepage at the banjo fitting on one rear wheel which I tightened a bit and it seems OK now.

Today I enlisted an assitant to press the pedal while I went around and bled each wheel again (twice). No air bubbles from any bleed nipples now. I've adjusted the shoes on all wheels to be 1 click less than locking the wheel. The pedal now becomes firm, but not until it's about half way to the floor. I'd like it to be a bit higher. Can I adjust this by lengthening the pushrod or is there some other way?

[Neil MG]

Drive the car for a while to bed in the brakes and then try and adjust them up again.

[bmcecosse]

Slacken back the handbrake cables in the cabin - then adjust up the brakes so they are rubbing slightly - then retighten the cables so the handle is where you like it. The pedal should now be good. The pushrod adjustment is just there to take up any 'slack' before the master starts to move oil - so if you can feel slack, by all means take it up - but always leave a 1/4" free movement.

[Greengrass]

Im glad yours go half way down
Iv just done all mine and same problem as you i think that must be the norm

[bmcecosse]

No - it's NOT the norm......

[54woody]

Thanks bmcecosse. I'll give that a try and let you know how I make out. From what I've been reading in various posts, it sounds like bleeding the hydraulic system is one of the areas that many people have trouble with on these cars.

[bmcecosse]

I find gravity bleeds the brakes out just fine - it's never 'let me down' so far.......

[54woody]

I find gravity bleeds the brakes out just fine...

Do tell.

[bmcecosse]

I've mentioned it many times before - some folks are in some doubt that it works. Jam jar with a little old fluid - clear plastic flexible tube that fits tightly over the bleed nipple - loose end of tube in the jar below the surface. Open bleed nipple 1/4 turn - press down brake pedal HARD and then very slowly let it back up. Then sit back on a comfy seat and drink a cup of tea/coffee/beer while watching the little stream of bubbles trickle down the tube into the jam jar. Close the nipple - top up the master cylinder and move on to the next nipple. If drinking beer - probably best not to attempt to drive after doing all 4 nipples........

[Greengrass]

Hmmmm ill try that also i need new brass sleeves in the brake pedel that should help me

[kennatt]

can't stand this talk of beer and nipples off to the pub .again

[mike.perry]

On the gravity feed system I find that it works better if the corner being bled is lowered on the jack so that it is below the rest of the system.
It is also an excuse for a tea break whilst you are waiting but don't let the system drain itself whilst you are away

[54woody]

Oy-vay! I'm starting to get really fed up with this.

I followed bmc's advice yesterday. Slackened off the handbrake, adjusted the rear shoes to lock the wheels and backed off 1 click. One-by-one I went round the vehicle, had an assistant press and hold the brake pedal, open the bleed nipple and bled the wheel, close the nipple, let up the pedal, on to next wheel. When finished, the pedal was reasonably firm but only after travelling half way (or a bit more) to the floor. Readjusted the handbrake, reassembled everything and put the car back on the ground.

This morning I went out to the garage to give it a try...the pedal goes almost all the way to the flooor before firming up! What's going on. I'm baffled and would REALLY appeciate any help.

[bmcecosse]

The brakes are just NOT adjusted up tight enough. Pull them ALL up hard against the drums, so they won't turn - how's the pedal now? Should be rock hard and right there. So - you need to ease back from that setting very slightly - but not much. Leave them rubbing a bit.

[Neil MG]

Are you sure the master cylinder isn't leaking Internally. Slight leak past master cup but not secondary (same as often happens on the MGA!) so no external signs of leakage. You can tell by pumping the pedal until firm and then pressing hard and waiting. Any movement of the pedal, (very slowly down or sometimes a sudden step down) is the indication you are after.

[Declan_Burns]

Neil,
You could very well be right,
We had a similar incident with a brand new M/C here recently.

[54woody]

bmcecosse, I will give that a try. Might be a few days before I can get back out to the garage.

Neil, it's a brand new MC so I assume it's not leaking. Of course, that assumption could be wrong. I'll try what you suggest as well to see if the pedal sinks.

[54woody]

I managed to get out to the garage for a bit this afternoon and here's where I'm at. The hand brake is released. I have adjusted the shoes on all four wheels so that the drums are locked solid. On the front wheels, I turned the forward adjuster to lock the wheel, backed it off 1 click, rotated the drum around (with effort) so that I could access the rearward adjuster, then turned it to lock the wheel.

Now when I push the brake pedal down, it stops and is firm with the bottom of the pedal about 1.25" from the floor. If I pump the pedal a few times, it'll stop and be firm with the bottom of the pedal a tad over 2" from the floor. I pressed the pedal down very hard and held it for several minutes. There was no indication that the pedal was sinking at all.

I had expected, as bmc suggested, that in this scenario the pedal should be firm right up near the top of it's travel not halfway to the floor. What to do next?

[bmcecosse]

Well yes - I would have expected it to be right there at the top. The fact it pumps up suggests still a bit of air in there - but the pedal not sinking down tells me the master cylinder is not leaking. Is there any 'free play' in the pedal which could perhaps be eliminated by adjusting the push rod that leads into the master cylinder? There must be a tiny bit of free play to make sure the master cylinder gets back to the zero position, but any more just shows as long pedal travel.

[54woody]

It's a Christmas miracle! Woody has breaks!

There was probably about an inch and a half of free play movement (at the pedal). I adjusted the pushrod so that there's now around 1/4" free play. Low and behold, with the shoe adjusters backed off 1 click I now have a firm pedal at a reasonable height. Woo-hoo! Thanks all.

Now...on to the next task.