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Bleeding brakes

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pkmh

pkmh

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Hello everyone. Last time I was here was when I was rebuilding my HD8 SU's and I must say, all is very well with them now (terrific in fact).

Now I have a new headache regarding the brakes. Any advice would be greatly appreciated.

Last week, I attempted to bleed all my front and rear brakes, with my friend at the pedal and myself at each brake nipple, starting with the passenger rear, then the driver rear, etc. and through a coordinated effort when to open and close the nipples.

During the process, my friend indicated to me how resistance was been felt on the pedal and I noticed at each brake nipple how air and fluid would be discharging. but after numerous attempts, the pedal just ended up spongy or having no resistance. For the moment, I have to assume the bleeding process was done conventional and correctly.

All brakes have been rebuilt (front) and replaced (rear), with all new flexible lines and a newly installed brake master cylinder. We did noticed two leaks occurring at the brake reservoir and the master cylinder's brake line leading from the unit. Those leaks have since been repaired.

I will try bleeding again. Maybe those two leaks are the cause of my failed attempts. If attempts should fail, I thought about the idea of installing a type of air tight flexible tube above the reservoir and applying pressure during the bleeding process. This may require a third hand.

Another thought...Because the rear brake cylinders were discharging fluid and air, then can I assume the brake booster is functioning correctly (or enough so I do not have to bypass it with a new brake line, which is what I intend to do if it should be rendered useless).

Any other thoughts or advice?

Thanks for any input.

Paul
 
HI If there were leaks it would not let you bleed the brakes correctly. Generally these brakes do not take kindly to pressure bleeding. I would just try again with the help of your friend now that the leaks have been repaired.--Keoke
 
Hello,

an important issue is, meanwhile you bleed the brake pipes, that you fill all time enough brake fluid in the reservoir.That you can avoid that new air comes in the pipes.
If I bleed the brakes manually, I let my partner press against some pressure resistance. (I do not full open the bleeding screws)
Start with the longest distance.

So hopefully you are able realise the challenge.

Bye michel- who will weld the "dog legs" on weekend
 
Paul

You might want to try placing one end of a flexible/tight-fitting tube over the nipple, with the other end submerged in a jar of clean brake fluid. That way any backflow will draw brake fluid into the system, not air. Another tip, though I haven't tried this myself, is to put teflon tape over the nipple threads to help prevent air from being drawn past the loose threads and back into the system.

BTW, although I keep my Healey in western Mass, my office is down the street from you in Edgewater.
 
Paul,

Not to tell you what you might already know, but when bleeding the brakes with a friend on a Healey, keep the following in mind.

1. Bleed the master cylinder first.

2. Bleed the lines at the junctions. Those fittings can trap air.

3. Bleed the booster.

4. Recheck the reservoir frequently and keep it topped off.

5. If you empty the reservoir and suck in air, go back to the beginning.

6. The bleed procedure requires your friend to hold the pedal down until you fully close the nipple.

7. You should not open the nipple any more than you need too allow fluid to flow out, and you should close it BEFORE fluid stops coming out. In other words, reseal the opening in mid stream.

8. If all else fails, try bleeding with the car running so that the booster is activated. This will really push the fluid out, so be careful, but it also helps push out stubborn bubbles.

9. If the system continues to pass both fluid and bubbles, you have a leak somewhere. You can usually isolate the leak by identifying which bleeder is still passing bubbles along with the fluid.

I hope this helps.

Bill
 
Hey everyone,

Thanks for all the good advice.

I am here to give a progress report of what has transpired today with regards to bleeding my brakes consisting of good news and "maybe" bad.

We repeated the process of bleeding as we did on that previous day. All of the above advice was discussed and considered.

What has happened today, after pumping the brake and bleeding away, was the discharging of fluid appearing in a milky white substance from all brakes. We were confused what was going on. THEN, yet another leak was noticed. This time from the brake line going INTO the master cylinder. It was not as evident for no signs of wetness at that connection was noticable.

After tightening that connection, true resistance was being felt almost immediately and the fluid being discharged was now becoming clear, not milky or consisting of an air/fluid mixture. This also suggests to me the brake booster is still working. So far, problem solved.

So now the "maybe" bad news is this...

After pumping the brake pedal (and quite a bit I might add), my friend suggested I check to see if there was any wetness from inside the car interior at or above the brake pedal. After investigation of the master cylinder from inside and after removing the rubber dust boot, there was signs of wetness where the circlip is by the rubber seal. I am not talking about alot of wetness but say enough to create several drops of fluid building up there. I still have very good pressure on the pedal.

Is this normal or should I consider replacing with a new rebuilding kit? What bothers me is this master cylinder is a brand new part.

I remember when I took the old clutch master cylinder out as well how I noticed these aluminum shims used. Should I also consider using shims on the brake master. I am bringing this up for maybe it is an alignment issue with the master, not sure.

Just trying to figure out why this leak is occurring or if it's normal.

Any opinions what should be done here?

Thanks so much!

Paul
 
I was told (decades ago)to soak the rubber components of the master cylinder and brake cylinder in brake fluid prior to assembly. I've never looked inside afterwords because they never leaked out of the caps (and they worked). I never gave it another thought. I would "guess" that those components would swell in time and not seep any more. Are you using Dot3or4? Have you changed to Dot 5 without flushing out all of the 3 or 4?
 
I just replaced a clutch master because I saw some greasiness coming out of the rubber boot. Turns out the grease was just something that was apparently put in originally to reduce friction where the pushrod contacts the piston. The cylinder had some signs of wear so I replaced it anyway. The new cylinder came with instructions to 'bench bleed' so I did that, and that made the bleeding process much easier and more effective.

You should be able to disconnect the pushrod from the pedal, pop the circlip and have a look to see if you're leaking or there's just some grease in the cylinder before you remove it. A new M/C shouldn't be leaking at all, unless the seal has hardened or cracked.

The shims are used to lower the pedal height (nothing do do with alignment). They aren't generally used on the brake M/C.
 
Just let it alone for a bit but keep a check on that position it may have been just the bedding in if it appears to be OK then fill the void in the end of the cyln with red rubber grease and close the rubber cap--Fwiw--Keoke.
 
Thank you all again for your great advice. I will first keep an eye on it, then apply the grease idea.

But if worse come to worse, then next step would be to replace the seals with a new rebuilding kit. At least all can be done without having to remove the master already in place.

Again, thanks all!

Paul
 
What is the story with the "newly installed brake master cylinder"? My first thought is that it is the culprit. Bleeding the brakes on a Healey is an easy, simple, straight forward process. We did it in the 60s, the 70s, the 80's and even today - without everyone else finding a gazillion different reasons why it wont properly bleed. It's a no brainer. If your fittings are tight, and you can't bleed your brakes then the master cylinder is bad. Did you rebuild it? By any chance is it a "County" product?
 
Dang I wish I had of known that----Keoke-- :lol:
 
Got the note about the Master and if it's a county product.

All connections are now tight. I will check on the Master from inside to see if it's defective. It is a new product from B.V. That's all I can say at the moment. Thanks for the info. Much appreciated!

Paul
 
that County fella has a bad reputation---Keoke-- :laugh:
 
Hi All,

Just a quick comment. Many, when bleeding brakes, pump the peddle rapidly before final pressure is applied. I have found that a regular but much slower pumping action is more effective when bleeding brakes.

Ray (64BJ8P1)
 
Yes Rac,

I thought about slowly pumping the brakes instead of rapid pumping.

But because there was a total of four leaks, that may explain why my partner was doing the rapid approach. And pumping rapid seems to make for a nice fluid/air mixture as I've witnessed.

This afternoon, I inspected the master from inside the car. There is slight evidence of fluid present. Probably best I get a new rebuilding kit and start the bleeding process over again.
 
I had a very similar problem with a Jeep Wrangler. Did a total brake system overhaul including new calipers. After numerous bleeding attempts and several master cylinder changes I could never get any pedal resistance. I finally gave up and took it to the Jeep shop and after considerable expense and much embarrassment they determined that I had reversed the new calipers. When you do that the calipers are upside down and won't bleed properly. The Healey has right and left hand calipers so if you replaced them it might be worth checking.
 
Rich,

I don't think the brake calipers were the issue. The fact that the bleed nipples are more located at top of the calipers than the bottom should be enough of a clue they are installed properly (unless you did a total flip, then the bleed nipples would be facing outside and that can't be happening).

Honestly, I don't see how you can install the calipers any other way than one way only. True?
 
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