I'm posting this brake question here because I figure the track/racing forum members might be able to give me a better answer than the brake forum.

I recently purchased a set of used OEM Brembos to go on my 07 Enthusiast which is slowly turning into a track day car.

Anyway, tonight I was cleaning them up and loosening the bleeder nipples. Three of the 8 bleeder nipples would not budge. I sprayed them with some break-free and let them sit. When I came back I started with one of the front calipers and the nipple finally started to turn. But then it started turning too freely but would not come out or screw back in. Threads stripped. It did finally come out but the threads in the caliper are stripped.

I'm afraid I've ruined an expensive caliper. I'm not even going to try to remove the remaining two stuck ones until the soak over night.

Three questions:

1. Are there any options to fix this caliper? Could a machine shop do anything? Can you Heli-Coil aluminum? Would that even work on a hole that has to be fluid and pressure tight?

2. What should I do about the other two stuck ones? Even the ones that came out looked like the threads were rusty even though they look like they are made of brass.

3. Does anyone know the size/specs of these nipples? Are they a standard size? Easy to find?

Thanks for your help. I think I'm going to need it.

 

HeliCoil and you should be good as long as the seat is still good

 

Good. The seat looks fine so HeliCoil might work, but I've also found these:

http://www.levineautoparts.com/bleederrepair.html

which would be cheaper, easier and should seat perfectly.

Either way, I'm going to have a machine shop do the work.

 

That how Wilwood calipers come from the factory

 

Not sure I'd torque those to 30-35 lb-ft as stated in the instructions - on an aluminum caliper.

 

No, the torque specs are insane.

Here is the rest of the story. I took the caliper to the Nissan dealership to see if they would help. The kind of laughed and said they didn't do this sort of thing. They said it was pipe thread and there was no way to fix it. Took it to my local mechanic and he also said he couldn't help. He sent me to a machine shop. The machinist assistant said they could fix it, no problem, but he came back out with the machinist, who turned out to be someone I knew. He kept saying his taps would bottom out before they could cut enough thread. I think he didn't want to mess with it and that's pretty much the impression I got at several other machine shops. I don't blame them and sometimes the key is to find someone who just wants to help. I did not find that person today.

So, I gave up on professional help and headed to the two Meccas of DIY SNAFU nirvana, Harbor Freight and Pep Boys. I got the last two remaining bleeder repair kits (that I linked to above) at Pep Boys and got a $40 tap and die set from Harbor Freight.

I tapped the front caliper first. 1/8 NPT. It really did not need to be drilled. The threaded sleeve from the kit did not want to engage so I tapped the caliper once again going a few turns deeper. After that the sleeve engaged and seemed to torque down just fine.

I used heat (not enough) to try to get one of the two remaining seized bleeder screws out of the rears. The bleeder screw did finally give but it too stripped the threads out. So I tapped it too and it also seems to have worked.

One bleeder screw is still stuck and I have no more of the kits. Would love to unseize it without stripping it out but not sure it is possible. I may try applying real heat (youtube videos show bleeder screw glowing) at a friend's shop but still not sure it will help. So I'm ordering a few more of the kits off the internet.

I'm still worried that these kits, with my tap job, might not seal properly. I wish I could pressure test them off the car but don't see anyway I can do that. Wonder if a brake shop could do that?

Anyway, wish me luck. If they leak I'm pretty much out $900. Painful lesson.

 

Maybe get the threads started on the repair kits and then back them out and apply a thin coat of JB Weld to the threads. That should provide a good seal, just for insurance. Nothing to lose at this point.

 

I thought about that but I'm afraid to back them out again!

 

Gerorge
I got my "new" Brembo caliper couple of days ago. Both bleeder screws badly rusted. So far I have loosened one. Still working on the other, but I'm not sure I can get it out without stripping
May end up back with the Rock Auto version if this is not successful!!!!!!!!!!

 

I had the same thought with mine. I took the last seized rear caliper to my brother-in-law's shop and we heated the bleeder screw with a torch and it finally came loose without too much torque but I think the threads are still messed up. If so, I'll tap it too and put in another bleeder repair kit.

I'll be amazed if this all works out in the end. Live and learn.

 

Another question: Seized bleeder screws seems to be a common problem. How do you prevent it? I will need to bleed my brakes frequently and I don't want to deal with this problem every time.

I've read about things like Permatex high temp thread sealants that say they also help with disassembly. There are anti-seize compounds also.

 

I've tried 2 things which have worked to prevent seized bleeder screws. One is a very thin application of the Permates graphite anti-seize compound, and the other is a few wraps of Teflon plumber's tape.

 

Good to know. The teflon tape withstands the heat okay?

 

I've never had a problem with it. Spec sheet says melt point is 620F, but it may suffer some degradation before that.

 

Like I said on the other thread I think the problem is people torquing these little guys down way too much. The materials are soft metal (aluminum) plus the added effect of high heat. Then people worry about leaks and crank down on them too hard. I'm pretty sure this combination leads to many seized bleed nipples.

I was amazed at how little they needed to be turned when going between open and closed when I started bleeding my Akebonos for the first time. Since I nearly stripped my old (non-Brembo) OEMs calipers I learned to be very careful. I agree its a major worry since you have 8 chances to screw it up using a standard open end wrench.

 

I agree but on mine I think there were two problem. The first is that I don't think they have ever been opened. I don't know the year of the Z that they came off of but they bleed nipples looked like they had never been touched. So, years of being in place without ever being bled/opened. Second, the combination of two different types of metals is frequently problematic.

And you are quite correct about the torque required to tighten them. But it is counterintuitive. When you think about how much pressure they have to withstand and the critical importance that they do not leak it seems like you'd need some sort of thread prep and plenty of torque. The truth is that they only just need to be snug.

I have never owned flare nut wrenches but I just ordered a set to do this job. In the past when I needed to do a bleed I put the box end of the wrench on the nipple and then the bleed tube. Open end wrenches on bleed nipples and brake lines are a recipe for disaster.

As an update I have had to chase two of the brake line attachment female ends with a M10 x 1.0 tap to clean them up. Fortunately it worked. I've blown all the calipers out with compressed air so I hope all metal bits are gone.

My final concern is how much trouble I'll have getting the existing lines off of the car. Flare nut wrenches will help I hope.

 

I just said the same things in the other thread

If you haven't used PB Blaster, get some and soak the fittings the day before you need to crack them. It's amazing stuff and it's rarely failed me. Kroil is also good, but PB Blaster seems to work better.

 

I did and it didn't work at all.

Yep. I have sprayed it on nuts and bolts on old plows that have been sitting outside in a field for 10 years and the nut looks like a big rusty blob and it loosens right up. But with these bleed screws it didn't seem to do anything at all.

 

Good call. I might grab a flare nut wrench in the right size and just throw it in the "brake box" I take to the track. I've used a socket wrench before to break them loose, then switched to open end once I knew the fluid would flow.

My current problem is I keep losing those little black rubber boots that protect the nipple. I pull them off, bleed the brakes and then can't find where I put 'em!

 

I don't have much to add, but my bleeder screws tend to leak if I don't crank them down. I went out and bought some anti-seize just incase since I have them off and totally apart.