PC-85-928S

One of my longer M6X25 water pump bolts it not tightening on re-install.
Would a new bolt bite?
Would I slightly longer bolt bite?
Would a slightly wider bolt solve this?
Or do I have to go the time sert- route?
If so what size?

worf928

Helicoil will work just fine on a water pump bolt. Just buy the kit for the bolt size. M6x1.00 or M6x1.25 (check with a thread guage. I don't try to remember these things; I measure every time.)

https://www.amazon.com/Helicoil-5546.../dp/B0002KKPXK

You can do a Timesert if you want.

And no, new or longer bolts are not going to help.

Bilal928S4

Make sure that all the bolts you took out are the same thread and different lengths. Sometimes the PO might have put a different bolt in when he had a problem before. Other then that what Dave said.
Did you feel anything wrong when you took the old pump off?

davek9

I'd go w/ worf's Helicoil suggestion as he said works great, drill, tap, insert coil w/ Loctite and your done.

A good way to check the correct bolt length in the correct positions is to hold the water pump horizontal and place the bolts in the water pumps holes, all bolts should be extending through the pump body same distance/length.

IMO some people place the shorter bolts where a longer bolt should have gone and when correctly torqued it pulls out the leading threads, then there is not enough threads left to hold the correct torque.

mark kibort

actually, if its just one bolt and you have it all together, ive done this a few times sucessfullly. generally i do a time cert. but a helicoil will work fine.

Bill Ball

Yes, you could try a 5mm longer bolt. The holes do have extra bottom clearance and threads, and that should be adequate for these low torque bolts. You could chase the bolt hole and verify depth before trying the longer bolt. Helicoil is fine for this low torque application if you'd rather do an insert. Time-serts are better for anything using higher torque.

Glen McCartney

Another option would be to use a 7mm bolt. I had to do it on one bolt as I couldn't get a 6mm helicoil locally. Just used a 7mm tap and worked perfect, didn't have to drill the water pump housing to use it either.

PC-85-928S

I actually got it with a new bolt.
I strongly suggest new bolts all around with a waterpump replacement!

mark kibort

that might not give you the torque you need, but you could go just a tad longer and that would give the insurance you might want.
Ive done that before with great success.

Imo000

How rotter were the threads on thise bolts?