Brake Bleed problem

[Turbo36]

Hi all, I have a 69' 2000 Roadster with the Volvo front brake conversion. Due to some leaking I decided change out existing calipers for a new set. No matter what I try I can not get the pedal back, the first push goes to the floor. If I pump it fast I can get a pretty decent pedal but I lose it as soon as I release the pressure on the pedal.
So far I have pressure bleed, vacuum bleed and the go old fashion two person method but still the same; no pedal. After 2 liters of fluid thru the system I am at wit's end.

In frustration I tried the pedal with the pressure bleeder on the front and I had a decent pedal! Any idea what is going on or anything else to try?

[notoptoy]

Bleed the master cylinder first.

[Turbo36]

Bleed the master cylinder first.

I did bleed the master cylinder using the bleed ports in the side. I did not remove the master cylinder and bench bleed it.

[msampsel]

Is the master new? Maybe the new install has caused a weak master to fail.
Really just tossing out an idea.

[jheck]

I was having trouble getting my brake master to bleed. I ended up get a vacuum bleeder and it pulled all the air out.

https://www.amazon.com/gp/product/B00NP ... UTF8&psc=1

[AidanDawn2000]

Make sure your rear shoes aren't too far away from the drums and equivalent for the front.

[greydog]

How are your feeding the caliper cylinders? Do you have a block to feed the fluid to both ports on the caliper? Two lines? Cross drilled?

Sounds like you have air trapped in one cylinder of the caliper.

Dan

[jrusso07]

Three thoughts/guesses

1) Rubber hose may be expanding under the pressure due to age. Had that happen on my clutch hose. Not sure if you replaced brake hoses.
2) Air in line or calipers...try gravity bleeding by opening bleeder and let fluid run out....keep filling master...run alot of fluid until you are sure you get no bubbling. Do all 4 brakes. Dont use pedal. Then pressure bleed all 4 starting with right rear. Look for leaks on the lines as you gravity bleed.
I had a bleeder screw the would not seat properly...look of leaks at the bleeder threads.
3) There is a leak somewhere

[Turbo36]

All good suggestions, thanks.

To recap:
I started by replacing the rear wheel cylinders and shoes; power bleed the system but the pedal went to the floor due to a leak at i bad fitting , fixed that and got a very good pedal after power bleeding again and adjusting the rears.
After bleeding and taking it for a ride I noticed some of the front bleed screws had been leaking for some time so I decided to replace the calipers. This has the Volvo conversion that uses a "T" fitting to split the single hose (stainless, so no rubber hose) when I pulled the line from the Tee I quickly plugged it so there was very little fluid loss.
The only thing I haven't tried is gravity bleeding.

Yesterday I pulled the rubber boot off the back of the master and I can see that it has had a small leak for a long time as it was packed with " yellow gunk". Next Step for me is to order a new Master.



Because the pedal went to the floor when I had the leak at the rear fitting One thing has been puzzing me; is it possible that the brake monitor switch is leaking internally and causingthe split system to "merge" and act like a single system?

[GeoffM]

The Volvo calipers usually have more than one bleeder screw...are you sure you have all the pockets of air, especially in the upper portion of the caliper, bled?

[Turbo36]

Update:
I got the new master cylinder in UPS today, spent about and hour bench bleeding it until it was perfect, installed it on the car, power bled the front and back and still no pedal!!!!!
I am at my wits end. I think it is time to admit the brakes are smarter than me and put the car on eBay. I will take my lumps but I need to move on.

[greydog]

Obviously, there's something very wrong here.
When you power bleed the fromt calipers, are you getting fluid from them? I think there are two bleed fittings on the calipers...are you bleeding both until no bubbles? This may be of no help but before you throw in the towell and take a beating, here's what I did.
The '69 1600 has a similar brake setup. Stock drums on the rear, Volvo 240 calipers with the stock Datsun rotor turned down slightly on the front. I have braided lines n the front with the factory dual master cylinder.
I researched online and determined I'd cross drill the Volvo calipers so that the brake line would connect to one "pot" on the caliper. The fluid feeds thru the cross drill to the second "pot". The second pot "feet" port is plugged. No second feed line or fitting is used. The line runs straight into a banjo fitting on each caliper.
FWIW, I've had no trouble with the brakes, in fact the pedal is very firm (probably due to the braided stainless line) and will stop the car very qujickly.

Perhaps a process of elimination to pinpoint the problem would help. Why not pull both the front brake lines (one at a time) and cap them to see if you can get pedal. That should tell you if it's in the calipers, or farther back in the system. Maybe even pull the feed line from the master and see if you have pedal. If you work thru the system, a component at a time, starting at either end, you should be able to find it.
Dan

Dan

[Linda]

Speed bleeders? They work great.

Linda

[msampsel]

Some good ideas Dan

[Turbo36]

Update: 7/8/16 - I have determined that the problem is with the left front caliper.
I plugged the line coming from the master cylinder to the front brake port on the distribution block and I got a decent pedal. I then worked my way back to the left front caliper, cracking and plugging at every joint. I would get a good pedal at every joint, right up to the connection to the caliper. As soon as I hooked the hose to the caliper the pedal would go to the floor. Pull the hose and cap it and I would have good pedal again..
I have put a at least a quart through this caliper by pressure bleeding, manual bleeding and vacuum bleeding. Is it possible I got a bad rebuilt caliper?