Bleeders as installed are not at the top. Close but no cigar. I have been taking them off, sticking 1" spacers in there, and holding the caliper in my hand with the bleeder straight up.
One thing I do know is I am tired as hell of wiping brake fluid off the floor so the dog doesn't lick it!!!!
I did have a very similar problem with one of my race cars when I first built it. No matter how much I bled it, the pedal was soft. What I finally did was make a plug from a small finish nail that would just fit in the tubing. I started with this plug installed at the master cylinder (single circuit style) and was able to get a hard pedal. I then moved it fitting by fitting through the whole system. I was able to get a hard pedal at each connection. So I was eliminating a part of the system each time I installed the plug. The air bubble was somewhere in the rear plumbing and I was finally able to bleed it out. The funny part is that I totally disassembled the car that winter and when I put it back together in the spring, I had no problem bleeding the brakes using the caliper bleeders.
I probably did it wrong, but calculated a lot less displacement than your .6 cu/in. per 1/4" movement. I get .60cuin per inch of stroke. I;m also unsure of the caliper piston movement numbers, is that 1/8" for all four?
Checking the brake pressures at the 4 calipers was a hoot. It took me a while to figure out the size and thread pitch to use the right adapter and I lost a little fluid getting it in. So there was a lot of air in the system. I had my wife push the pedal to check the first front caliper. 600#. Not enough. told her to push with all she had. 700#. Now she is legally blind in one eye, but I had her read the gauge while I pushed the pedal. She says I had 1000# on both front calipers. That's good. Wilwood says not to exceed 1100#. Go to the rear and the gauges are hard to read due to the angle of the gauge in tight quarters. Wifey said about 900#. That's probably just about right. Get the air out of the system and I believe these numbers would be good. Mind you I had to pump it up to get these numbers.
Something just occurred to me. What if while I had the caliper off, I put a 3/4" spacer in to mock the 1" rotor. Pump the piston out, as long as this doesn't push the piston out of the bore, then use a c clamp to force the piston back to the 1" rotor position. That would pressurize the fluid back to the MC and maybe blow the air out the MC. Might be worth a try.
Thanks for the update. I am going to bleed the master and the lines one more time. If that doesn't work I am going to buy a gauge set.
Yeah you are correct. My math was wrong! I don't know how far the caliper piston has to move for engagement. I think I may put a dial indicator on one in the morning just to see what this movement is. Then we can make calculations that actually mean something.
If you can get one of those injector bleeders, you can push the brake fluid up to the master. Where is the master mounted?
I agree the 7/8" master should be doing the job at hand. What about shifting direction and calling the Wilwood tec line and see if they can shed some light. According to the info you have shared you should not be having any kind of an issue. You should be able to stop your car with less than 1/2 your total pedal movement on the first stroke. This just don't add up to me.
No it doesn't add up for me either. I tried Wilwood tech this morning. Waited on hold for about 15 minutes and gave up. I'll probably try again tomorrow. Brakes designed for a 4000+# car on a 2500# car ought to be able to stand it on its nose on the first hit.
I had the same problem with a hydraulic clutch slave cylinder. Tried gravity bleeding, no luck, it would flow, but not enough. Tried pump and release the pedal, same thing. Tried to push air down teh top of the master, only succeeded in blowing the plastic cap off. Buddy that was helping me called a buddy of his that ran a truck shop for advice, he told us to cycle the slave with a screwdriver to force the air back up through the master cylinder. Did that, and be damned if it didn't work first time! Maybe you could do the same by forcing the calipers back in with a C clamp or something?
Yeah I mentioned that earlier. Pump the piston out until you think its going to fall out, then push it back in with a c clamp. I haven't tried that yet, but that is probably on the agenda for tomorrow. Seems like it might work. Do it at each caliper even couple of times. Pads are about 1/2" thick each. When the pads wear all the way down the piston isn't falling out yet. I should be able to pump the piston out a little less than an inch and not fall out. Then push the piston all the way to the bottom of the bore. Leave it there and move to the next caliper. Get all 4 pushed to the bottom. Probably have to keep removing fluid from the MC the whole time. Then start pumping fluid into it from the MC pushing all the caliper pistons and pads out to the rotor. Hell, it's worth a try. I'm grasping at straws. It comes to mind that somebody's signature line here on the HAMB says something about the laws of Physics not being just friendly suggestions. I don't think any laws are being broken here, but maybe a little bent and battered. Can't be black magic.
Nope! that ain;t right because this is a floating caliper and the caliper body moves to make up for the outer pad wear. So only 1/2" of piston movement out. It's time to go to bed. I'm getting goofy. Tomorrow is another day. As long as I wake up!
Hey Jaw, I can sympathize with you. Out of all the fluids that we have to work with on automobiles I think brake fluid is the worst, it's got a combination of slimy/sticky and it's a pain to clean up. After reading through everyone's comments I would suspect the master cylinder of maybe being bad or maybe having an internal problem. Wilwood makes good stuff, I've got one of their MC's on my car, but there is always the possibility of a lemon getting through the system, particularly in today's manufacturing world. I'm no expert on brakes by any measure, but that's my guess. Do you have another MC you can put on and see if anything changes? (process of elimination type of thing) Outside of a motorcycle I've never had a vehicle with a low mounted MC so I'm not sure if there are problems specific to that mounting location, or if that type of mounting location bleeds easier or harder. It's no fun waiting on hold for tech personnel to answer either, not sure where Wilwood is located but with the Covid/workforce/supply chain mess going on they might be understaffed. I called them a couple years ago about a problem and had to wait a good 15 to 20 minutes as well. To get some additional help you might try calling Speedway Motors, Summit Racing, or Jegs and ask if they have someone on staff that is good with brakes. Last but not least, if I'm banging my head against a mechanical problem I'll leave it for a day and come back to it. Often our subconscious is working on the problem when we're busy with other things and the answer becomes obvious. Best of luck getting it solved, I'll keep following.
Can't advise on jaw22w's issue. Will advise that the cost of a vacuum bleeder is worth it the first time you don't have to ask the wife to help bleed brakes. Everytime after that is a bonus.
On the bleeders being on the top, and the calipers being moved to ensure this is achieved, and I'm sure jaw22w has this covered, but just to be certain, its not the bleeders being at the top that is important, its the place where the bleed tube is drilled to relative to the top of the cylinder that is important. This might mean that in some cases the bleeder might be at the top but the port is not at the top of the cylinder. Not talking much here, but we're probably not searching for much either. Chris
vacuum bleeders work good but if you have the slightest leak anywhere, it will just keep sucking air into the system through that leak.
Look for leaks at night, even if you have to put the car on stands. Go out in the dark armed with just a flash light. Leaks show up well with this method. Bad masters usually bypass, you lose the pedal but the next pump it is back to normal. They can be hard to ferret out. Post a picture of your caliper bleeders, I'm just curious. Back MANY years ago, the Chevy Vega was notoriously hard to bleed brakes and get a decent pedal. We used to talk on the phone with GM and they said, if you come up with something, let us know. Best results were with the back of the car higher than the front.
Well, I woke up this morning! So, another great day of trying to outsmart brake fluid! I have a few things to try this AM. If those don't work, I will try bleeding at each line joint.
The wife will come help most any time I ask, but sometimes is a little surly about it. We had a saying in the Ironworkers about working with some people. " I would rather have a good C-clamp as him for a working buddy." Getting the wife out to help is kinda like that.
The Wilwood D-154 calipers are pretty much a copy of the GM Metric intermediate car calipers that were on the car before the Wilwoods. The GM calipers are kind of misleading on where the bleeder port is as they are drilled and tapped for the bleeder at an angle. The Wilwoods are drilled straight, so there is no doubt when the bleeder is on top. The rear calipers are mounted so the bleeder is on top with aftermarket bolt on brackets. I don't have to remove them to bleed. The fronts however are mounted on the Speedway brackets that do not get the bleeder mounted on top. Like I said, close but no cigar.
I have the car on my 4 post lift on a clean garage floor. I have been aggressively inspecting for leaks. I haven't had any leaks, except for where I have been opening lines. I really don't think there is a problem with the MC as evidenced by the pressure achieved when testing with my pressure gauges. The MC is not bypassing fluid. The car has a pretty good forward rake, so the rears are uphill from the MC. The fronts are slightly downhill from the MC. I may try raising the front to bleed after the rears are bled out.
"But I can push the pedal to the floor after any number of pumps " would generally mean the MC is bypassing ?
Not yet. I did not have a male plug for the IFF fitting at the MC. So I soldered a fitting shut to make a plug before I went to bed last night. That is on the agenda for today. I'm having a little trouble getting going this AM. The fittings at the MC are in a difficult to access place. If I take out that rear MC fitting one more time I am going to have to replace it, due to the nut getting rounded off. Even using a line wrench on it. Can't get a good angle. Just one more thing.
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