Installing New Caliper

Gumart1 · February 25, 2006

I'm replacing the front driver's caliper and I cannot stop the leak. The leak is a fast drip that is originating from the bolt that attaches the brake hose to the caliper.

I did not have any leaks before. I used two brand new copper crush washers that were included with the caliper on each side of the bolt and torqued them to the correct 22 ft. lbs. I had a slow drip and when I tried bleeding the brake it really started leaking fast. Just for kicks I tighten the bolt even more but it didn't help.

Do I just have bad crush washers or is there another reason? Do the tiny holes in the bolt that allow fluid through need to be aligned with the hole at the end of the brake line (hard to explain without seeing)? If so, every time I thread the bolt it will not end up in an aligned position.

Second question: I just flushed the fluid from the other three brakes before I found that this caliper needed replacing. Because of the leak, my master cylinder dropped below the minimum line, but did not empty completely. Do I have to bleed all the brakes and the master cylinder too, or just the one I am working on?

mehullica · February 25, 2006

Is the hose alignment pin lining up with the caliper? Aftermarket caliper or OEM?Is so you might have a cracked bolt, or caliper. The master cylinder front port is for the rear brake and the rear port is for the front brakes, sure you went low on the front port, so bleed the back brakes.

Arkansawyer · February 25, 2006

If it didn't empty completely you should be fine. Before I flushed my brakes I took a turkey baster and got all the fluid out I could. There was still some left that I could not get out of the m/c. My point being that even though I couldn't even see any fluid through the side of the m/c there was still fluid inside.

I would try getting a couple new copper washers and try it again. The holes do not have to line up.

Gumart1 · February 27, 2006

Thank you both for your suggestions. Finally found the problem today. One of the old original crush washers had worn down to almost nothing and had "melded" onto the bolt. I guess they take a beating just like any part with 250k miles. I didn't notice it as it was almost imperceptible to the eye, but the worn washer surface was not level, therefore causing the leak with the new washer sitting against an old washer. I haven't reassembled it but I'm sure this was the problem. :)

Arkansawyer · February 27, 2006

Yes, those washers are to be replaced each time you break the line loose. Have reused them in the past when in a pinch but not recommended.

Yes sometimes the old washers are hard to spot when, as you say, they become "part" of the bolt.

SKperformance · February 27, 2006

Buy a new crush washer to replace the new one that leaked as any dirt or odd surface will etch them and cause a leak again sooner or later.

Gumart1 · March 1, 2006

Part II - I removed the remnant of the old washer, cleaned everything thoroughly and installed the new crush washers and all is good, no leaks.

However, I just tried bleeding this last brake and the fluid just doesn't want to flow! I understand that the fluid has to find it's way through the caliper first, but after many attempts, all I get is about an inch of fluid that appears at the clear tube but doesn't push through. The brake pedal feels like a rock and there isn't much movement.

One thing I want to add is that when I flushed the first three brake lines, the traditional method of pumping and holding the brake pedal down on the last pump while opening the bleeder screw gave me almost nothing. What worked for me was having my helper be on the downstroke as I opened the valve and then continue to pump. Enough fluid was working it's way down the tube to prevent any air going back. Does this mean air is trapped somewhere in each line?

I only flushed in the first place as preventative maintenance. Braking beforehand was strong and smooth.

One thing is for sure, my wife's (helper) getting tired of helping and her foot is getting strong enough to kick me in the %^@!

Arkansawyer · March 1, 2006

There are two ways that I have seen brakes bled. The first being the traditional method of pumping the brakes several times then holding the brake on the downstroke then opening the valve while the helper continues to push the pedal to the floor. Once to the floor close valve.

The other method is to pump up the brakes as above but on the last pump allow the pedal to come back to the full up position. Opening the valve then having the helper push the pedal to the floor then close valve. This method allows for a longer stroke and more fluid to be pushed out.

Both of the above are done with a tube snugly attached to the bleeder valve and running into a jar that is filled with brake fluid. This ensures that if the valve should open while pumping it allows for fluid to be pulled in and not air.

IMO, I would never intentionally pump the brakes while the valve is open. Too much chance for air to be sucked into the brake line.

Threadcutter · March 2, 2006

Part II - I removed the remnant of the old washer, cleaned everything thoroughly and installed the new crush washers and all is good, no leaks.

However, I just tried bleeding this last brake and the fluid just doesn't want to flow! I understand that the fluid has to find it's way through the caliper first, but after many attempts, all I get is about an inch of fluid that appears at the clear tube but doesn't push through. The brake pedal feels like a rock and there isn't much movement.

One thing I want to add is that when I flushed the first three brake lines, the traditional method of pumping and holding the brake pedal down on the last pump while opening the bleeder screw gave me almost nothing. What worked for me was having my helper be on the downstroke as I opened the valve and then continue to pump. Enough fluid was working it's way down the tube to prevent any air going back. Does this mean air is trapped somewhere in each line?

I only flushed in the first place as preventative maintenance. Braking beforehand was strong and smooth.

One thing is for sure, my wife's (helper) getting tired of helping and her foot is getting strong enough to kick me in the %^@!

Gum:

Have you looked into rebuilding your front calipers. If I remember correctly, each of your calipers has two pistons (?). I just did mine (1995, 4 pistons per caliper) & it's brain dead simple. Cost was about $30.00 for the minor rebuild kit for both front calipers. You get the cylinder O-rings & rubber boots for the pistons as well as about an eighth of a microgram of some really nifty grease. <_<

It sounds like you may have had some kind of an internal blockage for some time. And, it could be that there's rust inside the cavity of the caliper. Have you had any "weird" brake behavior? Any problem with warped rotor(s)? Also, remove the bleeder screw & check to make sure it's OK. Probably faster & cheaper to just replace the bleeder.

The "kid" behind the counter at my local auto parts store actually gave me some good advice that made sense. He said never throw away the "stupid" little rubber caps that go over the top of the bleeder screws. He said that the rubber caps are what help hold a vacuum when the brake pedal is released. Holding the vacuum is what slightly retracts the pistons/pads from the rotors & also keeps outside air from migrating into the system.

Gumart1 · March 2, 2006

Threadcutter - What started the problem with this caliper was simply that the bleeder screw broke right off when I opened it - didn't even use that much pressure. I had no problem with the first 3 brakes. There is another LS member on this forum that recently had exactly the same thing happen. So if I were to do it again I would use a lubricant to help loosen it first. But I truly did not force it. I really didn't feel like drilling out the bad screw and retapping and I tried all other methods to remove it.

For $40, I bought a rebuilt caliper with a lifetime warranty - it is a dual piston as my LS was made after July of 1990. This morning I removed the bleeder screw entirely and pumped the brake (knowing I would have air - I already had air anyway), and the fluid came out really quickly. So I knew the the lines were good. As it turned out I had to open the bleeder screw almost 2 full revolutions to get a good flow. This is what confused me last night and was the cause of the poor flow - all the others opened with a quarter turn. I was able to close it and so far everything seems fine. I haven't tested it yet. I didn't have any bad symptoms before the flush, so I believe I am good to go.

Some people have recommended replacing both calipers in the front. But I never had a problem with the caliper that I replaced - I suppose I will drive it and see if there is any remaining issue.

Your tip about the rubber cap is excellent! I saw it first hand tonight as I noticed that the fluid retracted slightly even after I closed the valve. When the cap was put back, after pumping again, there was no fluid movement. So apparently it is not just to keep dirt and debris out of the lines.