[Eric10905]

This is just an fyi story of caution. For those who do their own brakes, or even if you take them somewhere to have it done. Don’t make the same mistake I did.

It’s apparently easier than I would have thought to damage the seat. I did and now will be replacing a caliper since it has developed a small leak. ;-(

The rest of the story: When I bleed brakes, change the fluid, etc, I use an ignition wrench for loosening/tightening the bleed valve. Since this has happened, I measured the dang thing: < 3” from the center of rotation to the end. I can get two fingers onto it.

Anyhow, so after I bleed each valve location, I close it with this ignition wrench and tightened. I don’t throw my body weight into or give it ugg-a’s or anything. At least I never thought I have. Tried to figure out how much torque could I have inadvertently applied. I think 50 lbs of force would be a lot to put on this wrench with two fingers. And even if I applied at the end of the wrench (I can’t), that’s 150 in lbs, or 12.5 ft lbs. Not sure at what torque it will damage those seats either. But I managed to do that. Apparently I don’t know my own strength. Or stupidity.

I’ve never used my in-lb torque wrench when doing this (obviously). But can guarantee I will be going forward.

As a side note, it was a front passenger one, and I have the Zl1 1LE brakes up all around. MSRP for a new one was a spot over $1k. Most of the GM parts sites online had it listed for between $620 -$700. (One had it for $440, but didn’t order from there, different story). I found it on Amazon for $516, delivered in 4 days. I was surprised. Pays to shop around i guess. Received it Saturday and it's the right part, new, and looks good. However, as I write this, I noticed now they have increased the price to $668. (They still show the front driver side 172-2819/84229190 for $293…)

Keep it on the black stuff (and don't over tighten small fittings).

[sr71bb]

Originally Posted by Eric10905

This is just an fyi story of caution. For those who do their own brakes, or even if you take them somewhere to have it done. Don’t make the same mistake I did.

It’s apparently easier than I would have thought to damage the seat. I did and now will be replacing a caliper since it has developed a small leak. ;-(

The rest of the story: When I bleed brakes, change the fluid, etc, I use an ignition wrench for loosening/tightening the bleed valve. Since this has happened, I measured the dang thing: < 3” from the center of rotation to the end. I can get two fingers onto it.

Anyhow, so after I bleed each valve location, I close it with this ignition wrench and tightened. I don’t throw my body weight into or give it ugg-a’s or anything. At least I never thought I have. Tried to figure out how much torque could I have inadvertently applied. I think 50 lbs of force would be a lot to put on this wrench with two fingers. And even if I applied at the end of the wrench (I can’t), that’s 150 in lbs, or 12.5 ft lbs. Not sure at what torque it will damage those seats either. But I managed to do that. Apparently I don’t know my own strength. Or stupidity.

I’ve never used my in-lb torque wrench when doing this (obviously). But can guarantee I will be going forward.

As a side note, it was a front passenger one, and I have the Zl1 1LE brakes up all around. MSRP for a new one was a spot over $1k. Most of the GM parts sites online had it listed for between $620 -$700. (One had it for $440, but didn’t order from there, different story). I found it on Amazon for $516, delivered in 4 days. I was surprised. Pays to shop around i guess. Received it Saturday and it's the right part, new, and looks good. However, as I write this, I noticed now they have increased the price to $668. (They still show the front driver side 172-2819/84229190 for $293…)

Keep it on the black stuff (and don't over tighten small fittings).

While we are on the subject of caliper maintenance another COMMON mistake is to overtighten the two large 18MM caliper bolts and in the process strip out the threads. I tighten these bolts NOW NO MORE than 110 ft. lbs using BLUE loctite.

On a side note, what makes a caliper side dependent is a couple of things. ONE the BLEEDER valve is always at the TOP side of the caliper.

TWO as in the case of ZL1 brake there are THREE different size brake pistions in each side of the caliper. The BIGGEST piston should be the CLOSEST to the bleeder valve which is at TOP side of the caliper. The smallest piston is at the bottom portion of the caliper.

The reason I mention this is that I had a caliper that had the bleeder valve at the top BUT for some unknown reason, the smallest brake piston was also at the top of the caliper as well. So the brake pistons were in reverse order of what they should have been.

The result of all this was the RIGHT correctly configured brake caliper would grab harder and quicker than the LEFT which made the car pull to the RIGHT under HARD brake pressure.

So the moral of the story here is TWO right side calipers wont work even if someone switches out the bleeder valve to the CORRECT location.

The OTHER thing to watch for is the brake pad retention bolt that goes through the CENTER of the caliper and helps stiffen the caliper. If you take this bolt out frequently to change pads the HEAD of the bolt that is normally held tightly by the calipers so that it doesnt spin can eventually wallow out the portion of the caliper that holds the head of the bolt in place. So dont over torque the nut that holds that bolt on.

I machined a slot in HEAD of my bolt so that I can hold it with a screw driver while I tighten the nut.

[Eric10905]

Hey Greg, nice idea with the slot on the opposite side head.

I've noticed the different size pistons, but never paid attention to which is at top/bottom. While I don't feel any pull to one side, I'm going to have to look when I change pads again. ;-)

[sr71bb]

Originally Posted by Eric10905

Hey Greg, nice idea with the slot on the opposite side head.

I've noticed the different size pistons, but never paid attention to which is at top/bottom. While I don't feel any pull to one side, I'm going to have to look when I change pads again. ;-)

THX. And the situation with the caliper having the pistons in the wrong location was self inflicted somewhere along the line. I had a couple of sets of calipers I sent out to have CERAKOTE'ed and I should have checked them when I got them back but I didnt. I probably have TWO Left side calipers over there somewhere at the CERAKOTE shop (LOL).

The cerakote by the way holds up VERY WELL. They have a satin finish which I think helps and the texture as you can tell from the pics is very thin with some grit to it. They will easily clean up with some dawn detergent and a rag.

[mikem2104]

so interesting timing, i'm having a similar issue. i'm not at the point though where i believe the caliper is damaged. i just cant see how it could be THAT easy to damage the seat if the threads show no issues whatsoever.

it appears to be such a rampant issue for people including vette, camaro, caddy v series, gt350 ... weeping around the threads.

Mechanic or otherwise, i just doesnt make senese. i pulled a few bleeder valves, and they look fine. no scoring, no thread damage whatsoever.

i'm going to blast them to some brake clean, maybe add some high-temp thread sealant and see what happens.

wondering if anyone else has experience with this a the torque value they used to solve the issue. i've seen a few post from reliable people alluding to needing more torque than they expected. wonder how much

[Alpha1BC]

The torque spec for the Brembo caliper bleed valves on all of these cars is 13-15 ft-lbs. (17-20 Nm). If you're not tracking the car or otherwise frequently changing brake fluid that should be fine, but subjectively it feels like quite a bit to be doing if you're changing fluid every year or more frequently. I recently switched to using only about 10-11 ft-lb and haven't seen an issue for doing 1-2 fluid changes a year.

[Eric10905]

Originally Posted by mikem2104

so interesting timing, i'm having a similar issue. i'm not at the point though where i believe the caliper is damaged. i just cant see how it could be THAT easy to damage the seat if the threads show no issues whatsoever.

it appears to be such a rampant issue for people including vette, camaro, caddy v series, gt350 ... weeping around the threads.

Mechanic or otherwise, i just doesnt make senese. i pulled a few bleeder valves, and they look fine. no scoring, no thread damage whatsoever.

i'm going to blast them to some brake clean, maybe add some high-temp thread sealant and see what happens.

wondering if anyone else has experience with this a the torque value they used to solve the issue. i've seen a few post from reliable people alluding to needing more torque than they expected. wonder how much

Hey Mike, well, I hope you're able to solve yours without a caliper replacement!

I went through several stages on this, which included doing some maybe silly things to just make sure it wasn't that. That included replacing the bleed screw twice, and changing how much I tightened it. I tried cleaning out the plug hole and plug several times, etc. In the end, it always had some level of weep past the plug. I gave up and ordered a new one that I'll hopefully put on this week.

As for damaging easy, I don't know. Despite my "analysis", I bet I wasn't paying attention and leaned into my ignition wrench and torqued the heck out of it. I don't know but I think our calipers are (cast) Al and honestly not sure about the plug screw. But someone else said maybe the screw is steel, so in relative metal hardness, it might not be that hard to damage a seat. I just was warning that you might want to use a torque wrench, so you at least know consistently what you are applying, whether within the spec or not. Given my experience, I have lost faith in myself to trust that i torque it consistently each time and location... Good luck, let us know if you solve it without replacement.

BTW, not so sure i would try sealing with the threads, at least that is me.

Edit: on mine, the plug still screwed in easily by hand, so i also suspected it wasn't the threads.

[Eric10905]

Originally Posted by Alpha1BC

The torque spec for the Brembo caliper bleed valves on all of these cars is 13-15 ft-lbs. (17-20 Nm). If you're not tracking the car or otherwise frequently changing brake fluid that should be fine, but subjectively it feels like quite a bit to be doing if you're changing fluid every year or more frequently. I recently switched to using only about 10-11 ft-lb and haven't seen an issue for doing 1-2 fluid changes a year.

Thanks for this, i was going to be looking for the values next. i might also try a little lighter and see if it seals. i do change fluid twice a year (or more) as well...

[N Camarolina]

When you guys say your calipers are weeping, how much fluid is exiting and how often?

I ask because I've seen that after you bleed or flush the fluid, there is residual fluid inside the bleeder screw/housing that ultimately weeps out during track days. It does it once however, and not again (until the next fluid bleed/swap). You can minimize this by rolling up a little shred of paper towel and inserting into the bleed screw opening to soak up what's inside.

Or is it weeping each and every time you use the brakes heavily?

[Eric10905]

Every time I applied brakes.

An example. I found this after my track day where I had freshly bled brakes and changed fluid brand for the start of the year. Knew I had cleaned them after bleeding.

[2004YZFR1]

Originally Posted by Eric10905

Every time I applied brakes.

An example. I found this after my track day where I had freshly bled brakes and changed fluid brand for the start of the year. Knew I had cleaned them after bleeding.
Attachment 1124418

Did the brake fluid damage the paint on your calipers?

[mikem2104]

So i bought myself a torque wrench and was surprised that mine took additional torque vs what i thought i could safely apply naturally with a 11mm open wrench. So thats interesting for me.

The other thing i noticed for me, the interior of the bleeder valve appears dry, so im thinking residual. I redid the job and then dumped a ton of brake clean into the bleeder valve to clear it out. Will report back in a few days.

Your issue was only on the one calliper? That does look like a lot of fluid. Was the inside of the bleeder full as well?

My logic here is that if it is leaking, there should be fluid inside the valve body as well. Right?

[Eric10905]

Originally Posted by 2004YZFR1

Did the brake fluid damage the paint on your calipers?

Nah, it all wiped off. It’s just dirty from brake pad and track dust that day. ;-)

[Eric10905]

Originally Posted by mikem2104

So i bought myself a torque wrench and was surprised that mine took additional torque vs what i thought i could safely apply naturally with a 11mm open wrench. So thats interesting for me.

The other thing i noticed for me, the interior of the bleeder valve appears dry, so im thinking residual. I redid the job and then dumped a ton of brake clean into the bleeder valve to clear it out. Will report back in a few days.

Your issue was only on the one calliper? That does look like a lot of fluid. Was the inside of the bleeder full as well?

My logic here is that if it is leaking, there should be fluid inside the valve body as well. Right?

Just the one caliper. I hope. Since I have to install the new caliper, I’ll be bleeding them all again. And will recheck the others. Fingers crossed.
I don’t recall if there was anything in the bleeder itself. But if seat is damaged it will leak through threads without leaking through the bleeder screw. That was my logic and why I replaced the screw a few times. Let us know what you find…