macguyver

One thing folks ought to do -- & I learned this the hard way-- is when you send stuff out-- make sure you get yours back-- put an Identifying mark on it and let them know you EXPECT yours back-- I sent a set out to be powder coated and do not believe I got mine back as the threads were screwed up-- I think the fella intentionally does this to get folks to buy from him , but thats my opinion.

Do you know the bolt diameter and thread pitch??

Red89gt

No, I don't have that info on the bolt.

JCtx

It's a crapload of torque man, especially on aluminum calipers; that can't be right IMO. I've seen plenty of errors on service manuals before. That much torque I put on the rear exhaust clamps, and it was too much IMO. Put 12 ft/lbs on the front flanges.

I'd tighten it by hand, and just watch for leaks. I know the feel, but can't translate it into ft/lbs. I'd imagine it's not more than 18 ft/lbs. Or better yet, contact one of the top brake vendors selling aluminum calipers and ask them what torque they recommend, and go from there. You could also be dealing with weakened calipers due to excessive heat from the powdercoating process. I'd ask the powdercoater what temperature they're using. Some require 400º+, which can weaken some alloys, especially if you heat them twice. Good luck man, and please keep us posted.

Red89gt

Thanks, my friend that owns a shop said the manual had to be wrong and to do the same thing as I have always done installing new calipers. Light snug and check for leaks after bleeding the system. I have gotten a lot of people stating they use 30 ft lbs no problem, I wonder if it is a one time use at that value and they have had no reason to pull off the calipers once on the car. My reasons were the finish got marred and I sent them to be re-coated. Just wonder if anyone has ever had them on and off multiple times re-using that 30 value?

I used a torque wrench and the 30 ft lbs value just to not hose up the job. Just my luck, expensive luck.

JCtx

I forgot to add something that's obvious to many of us, but just in case: Test your brake system with a 'panic' stop, making sure ABS cycled. You want to make sure there're no leaks with maximum braking pressure. You can't be safe enough with brakes. Too little torque is as dangerous as too much IMO, so it has to be right. I'd definitely take the time to ask brake vendors for their input. That high of a torque sounds suspicious to me, but could be right. It's also VERY important to use NEW washers, since they could be compressible. Too many variables. Good luck man.

BEZ06

ELP_JC has some good advice, and like he says - even though the manual (both my '06 and '10 manuals) say 30 ft-lbs, that may not be a good spec!!

I looked on the PBR (the manufacturer of our calipers) site and can find a torque spec for the ones like they make for the base Vette, but not for GS/Z06 calipers - but they're the same aluminum so I don't know why the spec would be different.

Their spec for the inlet fitting for the calipers like on the base Vette is 30 Nm, which is about 22 ft-lbs.

I'm getting ready to swap on a new set of calipers onto my Z06 and I think I'm going to use that 22 ft-lb spec!!

Bob

Red89gt

22 ft lbs is going to be dangerous as well, 22 inch pounds maybe tops, I suggest tighten by hand and check for leaks. Just had a 15 hour flight to mull this over. Kind of kicking myself for using that high torque, I knew better but followed manual thinking it would be a quick easy install. You can probably get that much torque into the calipers once. Many have stated they have gone to 30 ft lbs, if they ever have to take those calipers off and reinstall I have a bad feeling we will here about it.

I always check the brakes on my driveway/private road before I get up to speed or on the roads.

Yes, I always use new washers, I have an ashtray on my workbench full of the used ones at this point. Ashtray of shame.

oldmansan

Sorry to be late to this "party" but this thread might be informative.

http://forums.corvetteforum.com/c6-t...njo-bolts.html

San

Red89gt

Hey San,

Thanks, and yes I saw this post when looking to see who else tore parts up following the 30 ft lbs spec out there. I will spray these posts everywhere hopefully preventing someone else from going that high if they search. Even 15 ft lbs is too much, that is 180 in lbs when converted, I will have to do a light snug most likely and just keep checking for leaks. If leaks give the bolt a 1/16 type small turn and check again, etc.

oldmansan

Sorry I saw this thread so late. I tried to warn others in my original post.

I've never had to touch the banjo bolts on my calipers. I've never had any leakage. I honestly don't think you will either.

30 ft-lbs is a lot of torque, especially on an aluminum caliper. I tend to over-torque fasteners, but I definately went easy on the banjo bolt.

San

Red89gt

I take it you just snugged the bolt by hand and called it a day?

oldmansan

I actually snugged it down with my small torque wrench. 14 ft-lbs is more than needed IMHO, but if anything I went a bit over. Bear in mind I have Stoptech calipers on all four corners, but I honestly don't know why stock calipers (if aluminum) would need anything more.

San

Red89gt

Well just did it like I have been for the last 20 + years.
Snugged with a combo wrench and its fine so far knock on wood, no leaks.

Bill Dearborn

Actually the dual diagonal system hasn't been mandated since the 70s. The early C5s 97-00 had front/rear separation. GM didn't put dual diagonal on the C5 until the 01 model year and have been using it since then.

Bill

stevebz06

I have heard that "click" type torque wrenches typically overshoot the desired torque. Is that what you're using? I don't recall ever using a torque wrench while installing banjo bolts on calipers and I've never had problems with leakage or stripping.

I guess you could try helicoiling the stripped threads, but probably you will end up replacing the calipers, anyway. I had to do that with a car when Speedbleeder people sole me the wrong bleeder screws for the calipers. Maybe I could have saved the calipers with a kit or JB Weld or something, but do you really want to go deep into a corner wondering if your fix will hold up?

As far as bleeding sequnce goes, I start with a front wheel to get all the old brake fluid out of the master cylinder quickly, then I go with the X pattern recommended by the service manual, and I usually do this 4 or 5 times a year, and especially before and after track events.