To understand why re-using TTY bolts is risky, you need to fully understand why and how they are used in the first place. The basic idea is that installing them to a specific torque value, usually just enough to ensure the assembly and its gasket are fully compressed, and then turning them a specific number of degrees beyond that point, ensures that each fastener is stretched equally. Stretching the fastener pre-loads it like an extension spring. This produces more consistent clamping forces than straight torque specs as there are many variables that affect final clamping force if torque alone is specified. The problem then lies in that if you re-use a TTY fastener that has already been stretched, you risk over stretching it and weakening or breaking it. Just snugging it up with loctite is less than ideal as well because you lose the pre-load. If you replace a TTY with standard grade hardware, then you would have to "re-engineer" the torque spec to achieve the same clamping loads. Upping the torque used to tighten a fastener carries far more risk in some assemblies than others. But distortion is certainly possible as TTY fasteners are most frequently specified in assemblies that are easily distorted (and dimension critical) or subject to rapid and repeated stresses.
If you don't have a torque angle gauge you can paint a mark on the bolt head and eyeball 50 degrees. I used to do that now I have a fancy torque wrench that lights up and vibrates when proper torque is achieved. I have also seen guys simply tighten with an impact gun and call it good.
Yes; that is what I did with this. I did not want to have to make my sister drive 18 miles one way to bring me a degree indicator. I put a mark on the socket; then a starting and ending mark on the flexplate. Of course in some situations that might not be doable. In the future if I do any engine work that needs to torque to degrees I will invest in a degree indicator that you can add to the break bar/ratchet as they are not that expensive.
That is an interesting gauge; I think it is used for piston position timing. My marking worked, it was just tedious to do on eight bolts. The trans is back in place, bolted to the engine but not torqued yet. Tomorrow is torquing the bolts and installing motor mounts. Oh, I need to bolt the torque converter to the flexplate, don't want to forget to do that, I better make a note and place it on the door so I see it when I go out.
usually used in combination to a torque wrench. The spec generally reads something like torque to 10 ft lbs, then an additional 60 degrees (for example)
They don't use anything like that in the factory, one big air motor with several sockets, tighten the bolts in a pattern to a set torque value, after that each and every bolt is checked for torque value by quality control inspector
I'm just saying that's not the way they do it in the factory, Metallurgy department checks randomly the bolts being installed, the bolts are designed for a specific tensile strength, they are rechecked down the line after the stress is stabilized,, and set if need be to the specific torque value. Over- torquing would result in a fragile Bolt
I went to put the bolt back in the bushing retainer for the stabiliser bar and the bolt would not start. I first thought that the bushing retainer was keeping the bolt from starting but after clamping it down, found that not to be the case. I examined the threads on the bolt and they were buggered at the end. I got my die set out and using the thread pitch gauge went to work determining the bolt. None of my gauges were a match and then it occurred to me that the bolt was metric threads. I did not have a metric thread die so that left me in a bind. The nearest place to buy fasteners was 29 kilometers away. I needed to install the bolt; leaving it out was not an option. I decided to do a little bit of hand mill work on the bolt. Using a small file and a good lens I set to work correcting the threads of the bolt. It was tedious work but I have done the same before. It was slow work but I managed to repair the bolt and was able to get the stabiliser bar bushing retainer bolted back in place. Today was not as productive as I intended it to be. I only managed to get one wheel assembly back together.
Yes, that is the way these are designed. No problem getting to anything when it is out of the engine bay. If you are on a fixed rate, you can not waste time taking an hour to get some hard to reach bolt out or, not having the room to remove something. Quicker to just disconnect wiring and hoses and such and drop the whole thing out the bottom. gmule you wouldn't have access to info that would tell me how much to torque the bolt subframe to body would you? Online searches are not turning up solid info. I am going to see if I can find the shop manual to my 93 Buick LeSabre and see what it says. Mine is a 1998 Buick LeSabre. Everything is just about ready to put the car back on the ground.
Not sure about your model, but.....I know subframe bolts on other related models are again tty.... Again, I've always reused them(as does almost everyone else). I use an air gun. If I were you i would re-use with blue locktite and a breaker bar.
None of the torque specs I saw referred to these as TTY bolts. I have only seen straight torque values. I use to have a family friend that worked at GM in the parts department and I would go to him with such questions and he would look them up or ask the shop mechanics. However, I no longer have that resource. I should tell my story about a code I once had on the car, contacted the local GM place and they never responded to me. So I contacted GM corporate with a complaint letter and got a response back but no help with the code.
66 lb. ft. "sequence" for tightening, if the entire subframe is dropped: a. Left hand poistion 2 b. Right hand position 2 c. Left hand position 1 d. Left hand position 3 e. Remaining bolts (sequence optional) Position 1 refers to the two front ones and “Position 3” refers to the two rear ones
