I spent an evening bleeding the brakes on my 1969 Lotus Europa and I ran into a problem with the front brakes. I'm running dual 3/4" master cylinders. The rear brakes are now perfect but I'm not getting anywhere on the fronts. The front calipers have been rebuilt and the masters are new. The caliper pistons aren't moving at all and the master goes to the floor with no resistance. I'm not getting any air bubbles out of the front brakes anymore and I've taken the front calipers off to see if tilting them would uncover an air pocket. There are no leaks and the flex lines are new braided stainless. I've just pulled the brake line off the master cylinder and blocked the opening,the pedal is hard as a rock so the master is good. Other than keep bleeding does anyone have any other ideas?
I've been going through the same thing with my 83 Urq...no air coming out anywhere but still no pedal. New master, 95 percent of the lines replaced, pressure bled, vacuum bled, and human help bled...still nothing.
Make sure none of the lines are at a higher level than the master cylinder. In other words the master shold be at the top. If there is a line higher you can get air trapped in there.
Did you you try a vacuum bleeder? I have seen bad masters brand new. A friend went through a couple brand new master cylinders on his Midget before one bled and held.
'Speed Bleeders' suck. I have never had any luck with them. I like the good old 'tubing and a jar' method. You stick a tube over the bleed screw, then drop it in a jar with enough fluid to cover the tip of the tube, then pump away at the pedal. As long as you keep the M/C full this works well, even if a bit tedious.
One method I have used before is this: you need a helper and the correct wrenches to loosen each fitting in the system. Helper pumps the pedal and holds it to the floor. You loosen the flare nut or fitting at the M/C and wait for air etc to quit squirting, then tighten it. Helper pumps again. Rinse and repeat. At some point you get only fluid when you loosen the flare nut or fitting. At this time, you go to the next fitting down the line and repeat the process. The key is for the helper to hold the pedal to the floor while you loosen, then tighten, the fitting, flare nut, whatever. You do this at each fitting until you get to the caliper. Go to the caliper with the longest line from the M/C (normally the right front) first when doing this, then go back to the closest one.
'Gravity bleeding' works well on hard cases too. You put a tube on the bleeder screw, open it maybe 1/4 turn, stick the tube in a jar with enough fluid in it to cover the tip of the hose. You then turn a plastic bottle of brake fluid upside down in the M/C reservoir, you will probably have to put a weight on it to keep it from leaking. Then leave it alone for an hour or two, you should see bubbles come out of the tube and finally only brake fluid.
If all else fails, get one of those big syringes and a piece of tubing, then open the bleeder screw on the caliper furthest from the master cylinder (that's normally the right front) and use the syringe to force fluid backwards from the caliper to the M/C. Messy but it generally works when nothing else will.
You night even try this: use the syringe and tubing on the bleed screw, but take the hose fitting off of the caliper. You then fill the caliper with the syringe and quickly reinstall the fitting, then bleed away as normal.
Jensenman, do you really mean right front... on every car I've ever owned ('cepting VW) the right rear has the longest run..... typo ?
The OP said he was having problems with only the front, so that's what I was referring to. You are exactly correct, if referring to all 4 wheels generally the right rear has the longest line.
wb jones wrote:
Jensen Man, do you really mean right front... on every car I've ever owned ('cepting VW) the right rear has the longest run..... typo ?
Depends on how they are plumbed. In the car I just did the rear is one tube all the way back to the center of the axle where it T's and goes to each caliper (there for same distance for either rear caliper) The front is almost always furthest to the right front.
Regarding the issue of note getting any pressure to the front brakes. It was pointed out to me today that there is a safty feature in some proportioning valves (I had forgot about this) I was thinking of removing mine and putting a manual one in my wifes mustang. What it is supposed to do is if you get a failure in either the front or rear brake system the proportioning valve is supposed to direct pressure to the remaining good circuit and cut off flow to the circuit that has no resistance. This way if you blow a line you can still stop the car. I recently ran into this in my mustang except that the system had failed putting all the brakes to the front (no matter what I did). I wonder if you have a bad proportioning valve or if you have so much air in the front circuit that the proportioning valve thinks it has a leak and is putting all the brake fluid to the rears. Or of the proportioning valve is stuck in the safty mode due to the bleeding of the rears first.
Just a thought.
dean1484 wrote:
wb jones wrote:
Jensen Man, do you really mean right front... on every car I've ever owned ('cepting VW) the right rear has the longest run..... typo ?
I wonder if you have or if you have so much air in the front circuit that the proportioning valve thinks it has a leak and is putting all the brake fluid to the rears. Or of the proportioning valve is stuck in the safty mode due to the bleeding of the rears first.
Just a thought.
this, even with the dual masters you may have a proportioning valve. Or if you put some sort of brake bias (other than a bar) it may be installed incorrectly. I had a mechanic do that once, not fun and similar results on the track to what you are seeing in the garage.
My MG had issues after a overhaul of the brakes. Turned out i had to bleed the MC by itself first, install, then bleed system. If this is obvious, please ignore.
I figure it might relate, betcha the orig Lotus brake MC is Girling just like my MG.
Twin master so were talking willwoods or tiltons?
If so call up Seven Ent the mini guys buy a ~$35 tool by gunson called EZ-Bleed. It a 1/2 quart jar with a hose and fitting to attach to a spare tire. The best presure bleeder i've ever used and the master cyl cap that comes with it fits most "racing" brand masters. You'll likley need to run 2 to 3 jars full but you'll have rock hard brakes afterward.
44
Just to clarify. The master cylinders are 3/4" Wilwoods with a bias bar. I'm using a 6:1 ratio hung brake peddle arrangement. The original master was a 7/8" single circuit Girling. The calipers are rebuilt original dual piston Girling units that were used on a ton of LBCs as well as Formula Fords. A fellow racer suggested that I'm not getting enough volume from the master cylinder in order to move the caliper pistons but I have a hard time believing that. This is my first time fooling around with a dual master set up.
you've got some sort of a bubble somewhere or the balance bar is not centered.
Make sure the Heim joints are spaced the same distance as the masters are. I've seen people way out and pinched in tight before on the balnce bars.
http://www.7ent.com/detail.cfm?pageid=36
The other thing is that the master (s) should be bench-bled before you install it/them. This ensures there's no air in the master before you even mess with the slaves at the wheels. It also tells you if the seals are bad before installation. If no got bubbles in the fluid when piston pushed (wid short tubes up 'n over inta 'd storage) , no got seals. Push piston 'til no got bubbles no more..may take a couple fills. 
You'll be able to tell.
Have fun! But it's really something minor like a kink in the line, or a bad flare not sealing.
I had a hell of a time bleeding the rear brake on my bike. I found a very, very tiny leak at a banjo fitting. After replacing the crush washer, it bled in no time at all.
Sorry I can'b be of more help. Please post pics of your MC setup, as I'm considering going the same way on Dr.Linda's S2. Oh, and make sure the balance bar is set so that the front MC is getting full stroke.
Jensenman wrote:
The OP said he was having problems with only the front, so that's what I was referring to. You are exactly correct, if referring to all 4 wheels generally the right rear has the longest line.
sorry, I missed the OP's reference ....it now makes sense ...
Comment on "Speedbleeders":
I bought a set of these for the Spitfire and installed 2 on the rear drums.
The threads/plating/threadlocker on the widgets make these a tough install on the TR wheel cylinders. I ended up running the 2 parts thru a 3/8 UNF die to reduce the diameter of the bleeders.
After that: They worked fine.
I contacted the Manufacturer and they basically stonewalled me about this problem.
So....If you use these...you may need to tweak them the same way...
Rog
