Bloody "bleeding" issue

[RDKeysor]

I don't know the answer regards Girling brakes, but I should have spelled Norman Nock's name correctly since I had his book on my desk. I apologize for that.

 

[kkaa]

Hi everyone, have an update!

So after thinking about the master being plugged off and being rock hard, we kept at it with kids taking turns and never got a peddle to stay. It was decided to bring it by a shop and see if there was something dumb we were doing and a quick fix. The guy struggled for hours and finally went for the master replacement and we have a $500 dollar hole in our pocket and a peddle, kinda. I brought it home because the best he could do was two pumps and its rock hard, but it still doesnt lock up any tires.

The manuals arnt that great at describing any adjustments so hope someone has ideas. On another item, I had replaced the rear shoes but not the front so just bought the bullet and have new front rotors and pads coming from moss.

Heres a video of the master that came out... https://www.youtube.com/watch?v=Ulb2nRgMXac

 

[steveg]

kkaa - did you ever bench bleed or recirculating bleed the new master?

I had a similar situation with my Fiat 124 MC which did not resolve until I hooked up the recirculating bleed pipe. This allowed me to pump the air out of the MC. The clear tube goes in the reservoir. The clear part allows you to tell when the bubbles stop coming. Then the mc should be air-free. Then proceed to bleed each of the wheels.
I like to use the syringe shown to pull the fluid out through the calipers, being careful not to allow air in past the bleed screw threads.

Mike Salter once told me he had a BJ8 (IIRC) where in order to get a successful bleed, he had to push the fluid upstream from the wheel cylinders, constantly keeping a watch on the reservoir.

There's also the gravity method where you jack the car up and let the fluid run out by gravity only.

There's a way to bleed this, we just haven't hit on it yet.

 

[PHulst]

Mike Salter once told me he had a BJ8 (IIRC) where in order to get a successful bleed, he had to push the fluid upstream from the wheel cylinders, constantly keeping a watch on the reservoir.

I have friend who works on a different make of British car, but similar vintage. This is the technique he recommended to me when I told him of the difficulty we typically have with Healeys.
He has a lot of success this way.

 

[dcarlg]

Do you have air leaking into the system somewhere?

 

[steveg]

Check out this previous thread:
https://www.britishcarforum.com/bcf...0-Bleeding-Brakes!&highlight=bleeding+brakes!

 

[Jack T]

Been following this thread off and on so I don't know if it's been mentioned before: Reversing the input / output lines at the servo will result in a rock hard pedal but no brakes. Does this car have a servo?

 

[twas_brillig]

oh, man! Nothing useful to suggest at my end, but sure as heck feeling sympathetic - and sure wish you (and the entire tribe) well. Annoys the heck out of me when 'simple' things, aren't. Good fortune to you! Doug

 

[kkaa]

HI guys, thanks for sticking with us on such a challenging "simple" project!

So to recap we switched the MC and have a peddle on the second stroke. If I try, i can bring her to speed and with a couple prep pumps get a good peddle and when i slam to the floor we can lock up. However, the brakes are still nowhere close to a good safe place. Fluid, all bleeders are pulling pure fluid, no visible air. In fact, i broght it to a local shop, they tried and same, just fluid and had no idea what it could be and didne even charge me. he first shop picked my pocket for $500!! after a full day. Hey, they worked and even thought we didnt fix, i guess its a fair result..

Question, should i just drive it for a bit in hopes to "unstick" any possible air? Were using dot 3, should i change to 4/5?

Thank you all for the help!!

 

[Bob_Spidell]

Are your hoses old? Could they be expanding under pressure? Presumably, the car was up on a rack at the shops; did you have a look at the hoses while someone was 'standing' on the brakes? If fluid's not leaking, and you're confident all the cylinders are good, something has to be absorbing the pressure in the system when brakes are applied. I'm assuming the drums were adjusted prior to bleeding? If not, the extra travel of the wheel pistons would rob you of some pedal.

I believe DoT 3 and DoT 4 are compatible, but you'd want to flush the system pretty well before switching. DoT is silicone-based; a very thorough evacuation and cleaning--typically, flushing with lots of denatured alcohol--is required to switch from glycol-based. The last MC I bought came with a warning that using silicone/DoT 5 would void the warranty, but I used it anyway. So far, no issues (but I've only got about 50K miles on it). I believe DoT 5.1 is glycol-based, and is compatible with 3/4. DoT 3, 4 and 5.1 all have different boiling points; mixing them would probably result in a fluid with the lowest BP, and the BP could be even lower.

 

[Deleted member 21878]

does the pedal act the same if you adjust all your drums up tight?

 

[Brinkerhoff]

I just finished a complete hydraulic restoration on a 59 TR3 that has the same Girling system : complete disassembly and cleaning and rebuilding of m/c , reservoir , calipers etc. new rear wheel cylinders. I use DOT 5 . Since the fluid inlet on the m/c is at the end of the cylinder pushing the brake pedal down increases the hydraulic pressure closing the internal inlet valve and pushes fluid out to the wheels through the center outlet valve which is the opposite of a Lockheed system . The short internal pushrod with the small inlet port seal must slide into the main piston when the brake pedal is pushed ( about halfway into its travel) or you'll get a "rock hard" brake pedal until this pushrod centers into the piston. Mine was a bit stubborn after I rebuilt the m/c but did free up and the brakes were able to be bled in short order.
Since brake fluid can't be compressed if you have no firmness to your pedal on the first pump of it you either have something in the fluid that is allowing it to be compressed ( air ) or the brake shoes or pads are moving on the first pump . Pull the rear drums to check for this and proper assembly.

 

[Novamonte]

I can't remember where, but I read somewhere (perhaps on this forum) about a rather easy fix worth trying if the pedal travels too far or if you have to pump several times to get a hard pedal. Just pump it up, keep it depressed and lock the pedal in the depressed position with a piece of wood or something similar. Let it sit over night and when the pedal is released the problem is fixed. I know it sounds like magic and I can't explain why it works, but it certainly did on my car. No more pumping, it brakes after an inch/a couple of centimeters of pedal travel or so.

 

[Rob Glasgow]

RE: Novamonte's comment from Apr 2018.
I Rebuilt my front calipers several months ago and had my wife help me bleed the brakes. No matter how many times we did each of the four corners, the pedal always had 2" of free play on the first push before you could feel resistance in the pedal. The brakes worked fine and after several pumps, the resistance came at about 1 inch.
Two days ago, I finally decided to give Movamonte's idea a try. Used a piece of 1"X2" and a reversed clamp to lock the pedal in the depressed position against the seat frame. The next morning, I measured the free travel and it is now 1" and on the second pump, 1/2". I can't for the life of me understand how this works since I never opened the bleeders but it obviously did something to reduce the free play. I haven't noticed any change, good or bad, in the braking, just less free travel of the pedal.
Anyone know why this would work?

 

[steveg]

Rob - Useful wisdom to add to the archives. Sounds like magic, but good to have it in the arsenal.
Assuming you're using DOT 4.

 

[Rob Glasgow]

I used to be troubled by not understanding why certain things worked without knowing the reason (with the exception of anything related to Calculus), but as I get older, I am willing to accept somethings are just magic.
Yes DOT 4.

 

[Michael Oritt]

Hi guys, check out the video and you can see where we are. Getting lots of bubbles back filling in the rez when you stop pumping, all bleeders are closed. Thinking this is good and will keep doing it thinking it's a simple place to bleed from.

https://www.youtube.com/watch?v=SaQOpNN2ZQE

This has been an interesting string and I'll agree that sometimes it is simpler to accept the result than understand why it turned out that way.

The video was most entertaining and I loved the soto voce aside to your partner "Keep doing what you're doing, Babe".

Glad things have resolved.

 

[Bob_Spidell]

This has been an interesting string and I'll agree that sometimes it is simpler to accept the result than understand why it turned out that way.

Just had a SWAG about why this might work: Keeping pressure on the MC might force a bit of air in the MC past the foot valve back into the reservoir. Theoretically, this wouldn't work since the foot valve, when compressed, should seal the MC completely from the reservoir, but I've had one fail (which required repeated pumps to get brakes; drove my BJ8 over a thousand miles that way).

Also suggest your assistant pump the brakes a bit slower; not sure why, but that's the way I've always done it and haven't had much trouble bleeding the brakes on a BN2 and BJ8. Do know that DoT3 is usually required for systems with ABS; supposedly Dot4 aerates from the rapid pulsing of the ABS servos. One thing that is certain is that your MC has air in it after the furious pumping.

 

[Bob_Spidell]

Hydrogen gas????

https://www.thetruthaboutcars.com/2...motors-recall-targets-zf-brakes/#more-1641052

 

[Michael Oritt]

The dog did it.