GM Brake Caliper Bracket Bolts

[Duelin]

I just got done reading a technical article about GM Started in 2007 using TTY bolts to hold their caliper brackets on. And the article went on to say that if the bolts have to be removed during brake repair service that they had to be replaced. Does anyone know which units use these TTY bolts. How many of you replace the bolts. How many of you use a angle gauge to torque these bolts to the correct specs. when you do a brake job. Since I retired I don't have the access to the info that I did when I was working.

[Jsdirt]

Sounds like something GM would do. Anything to make sure owners don't dare place a wrench anywhere on "their" vehicles ....

 

I haven't heard that personally, but that wouldn't surprise me in the least.

[Duelin]

I have been trying to search the back of my mind. To see if I could remember doing a brake job that might have had the TTY bolts. I don't think so but I hope not.

[Jsdirt]

I think that would be an excellent way for GM to get itself sued right out of business. Thousands of small shops and DIY'ers would re-use the bolts, with potentially catastrophic results - right on par with Toyota's sticky gas pedal.

[newdude]

Does not apply to trucks if I recall. Only thing they call for is threadlocker on the bracket to knuckle bolts. If its a 1/2 ton torque for the brakcet to knuckle bolts is 129ft-lbs. Caliper pin bolts 74 ft-lbs. TTY brake bolts seems to be a car thing...Cruze, Malibu, Sonic, etc. If it calls for new bolts do it though.

[Duelin]

Maybe if MS3DALE has time he can pop in here and enlighten us as to what models might use the TTY bolts. I was wondering about the cross overs and the small cross overs.

[Doug_Scott]

From my own experience, mechanics tend to religiously follow torque specs (along with honouring the replacement of TTY fasteners) inside the engine/transmission, and the further away from that, the less they follow specs.

Torque to yield fasteners are really no different to any other fastener, with the exception that they take those fasteners to their maximum torque value.

 

First time I saw a TTY spec was when aluminum cylinder heads came out. Seemed to be common on engines with aluminum heads and cast iron blocks.

 

Would not surprise me to hear that manufacturers have gone to smaller dimensional fasteners to reduce weight, and by doing so, they had to find a dependable way to get the maximum "tightness" of these smaller fasteners, without them breaking.

 

There used to be a common saying regarding torque, tighten till it breaks, then back off quarter of a turn. TTY has already found that point of breakage, and tells you how to get to the quarter turn before it breaks.