Quote:
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.