Lower steering shaft UJ bolts

I’m having to replace my lower steering shaft UJ,s again for 2nd time in just over a year. Replacement parts were Britpart & the UJ,s have failed already. Bought OEM ones this time that don’t come with new nuts & bolts. Can anyone help me with the size and whether or not they’re high tensile?

Stainless would do in that situation as there is only mild tensile/compression strength required.
I think I have an A4/80 M6 shoulder bolt in mine with a form C washer each side and a type P, deep, lock nut.
I think the original was a 1/4" (6.5mm).

Measure the hole ...

Yes, I was thinking of stainless.

Do not think stainless as this is a steering item and should be as the manufacture made. Although the shaft groove locates the joint the bolt has to be tight to prevent movement on the spline. 30 - 35 nm.

@tottot is right ... if the bolt needs 30Nm then stainless is no good at all as the max is around 20Nm ....

@Birdbrain , if you want st/st you can but it must be A4-80 grade bolts and do not use nyloc washers, use a st/st washer +spring washer + full length nut with at least three full turns of thread showing and do use Loctite. A4-80 have 600Mpa tensile strength and only buy from approved suppliers. I have been using A4-80grade for many years and never had a bolt or screw fastener fail. Try these guys to buy https://www.boltking.co.uk/a4-80

I get most of my SS fasteners from here ... https://www.spaldingfasteners.co.uk/a4-80-stainless-steel/

Cheers guys. We used a lot of stainless fittings at work before I retired so still have contacts with local suppliers. They’ve supplied me with core T bolts for propshaft UJ’s when a well known parts supplier sent the wrong ones !