I've been trying to track down a possible air leak into my '88 L98 TPI, and found a problem.

One of the four fuel rail bolts, which hold the fuel rail to the intake manifold, is completely missing. It's the bolt at the driver's side, rear. I'm thinking this could possibly lead to the fuel rail raising up a bit, and potentially creating an air leak between the fuel injector O ring, and the intake manifold.

What size bolt do I need to replace the missing one?

 

https://www.thirdgen.org/forums/tpi/...read-size.html

 

Thanks for your reply; I saw the same posting before having asked, which is why I had posted my question, for two reasons:

The poster did not specify a length;

And, the answer M6x1.0 was given more or less as a guess. As is all too common in forums, the original poster never confirmed whether this information was correct.

 

Take one of the existing three bolts off the rail and measure it or bring it to the hardware store and match it up.

 

I tried removing one of the other 3 bolts, they appear to be stuck. Since there's already one missing bolt in the fuel rail, I didn't want to chance snapping off one of the remaining 3.

I did try an M6X1 bolt in the missing spot, not even close to the right size.

 

Have you confirmed your size yet? Mine are easily accessible at the moment. I can check tonight if need be. That being said, I can't see one bolt missing causing a leak. My injectors are pretty snug, and the rail sits pretty flush on the manifold without the bolts. Can't see (at least on mine) any way that thing is moving with 3 bolts in it.

 

Are you talking diameter or length isn't close?

 

The bolt is an 8 1.5 X 36 MM

 

Judging by the way it went into the hole, diameter isn't close at all with an M6. No idea on length...so I'm back to square one.

 

Missed the earlier posting..M8x1.5x36 is exactly what I needed to know..thanks!

 

I pulled a bolt off my fuel rail.

It's an M8x1.25, 35mm or 36mm long (it's kind of in between - either length will work).

The old GM funky bolt - 10mm hex with 8mm threaded shank. Unless you get a GM replacement, the bolt from the hardware store will have a 13mm hex; make sure you have wrench clearance.

Put a flat washer under the head if you use a regular bolt. An M8 flat washer is about the same diameter as the flange on the GM bolt.

Torque to 15-22 ft-lb.