Suspension bolt specification

[Storer]

A question for those on here who have rebuilt their suspension or those "in the know".

I am about to replace the ball joints on my front suspension and am going to use new bolts. Are the bolts a specific type (metric fine, UNF, or ordinary metric) and what grade (8.8 or 10.2 or higher).

Hopefully somebody on here will know the specification.

[JensenA]

Steve Heath does a full Suspension bolt kit, IIRC the bolts are a non-metric 'English' size.

[mikesr]

The front ball joint bolts are ordinary metric size

M8x25mm top and M8x20mm bottom

I used zinc plated high tensile not sure what the actual grade was

[Ireland]

There's a mix of bolts on the Cerbs.

Some are metric and some aren't.

It really depended on what the donor part was off.

[350Matt]

For suspension I would go for 10.9's or 12.9's

see

http://www.boltdepot.com/fastener-information/Mate...

8.8 is the minimum spec you should use really for any application

If you ask for self coloured bolts ( black finish) at your fastener supplier then these are usually 10.9
Bear in mind tho, that these love to rust so use plenty of coppaslip

Matt

[Storer]

Thanks for the replies guys. Steve Heath offers a simple solution if a little expensive. He doesn't say if they are harder than 8.8 in his website though.

I have checked the parts book and there is no info on bolts.

Can't find suspension in the workshop manual either.

Stainless would be nice but the correct grade for each application is important as they are more brittle.

[cerbfan]

The grade 8.8, 10.9 etc is not just to do with the hardness of the setscrews / bolts its also to do with the tensile strenth. The allen key headed bolts for the ball joints are socket head cap screws and are generally only available in 12.9 grade.

8.8, 10.9 and 12.9 only relate to metric bolts whereas most of the bolts on the suspension are imperial UNF bolts so will have grades 2, 5 or 5.1 etc.

The bolts supplied in the Steve Heath kit tie up with what was fitted to my car previously, (although not to say that these were original) and are all UNF grade 5, which approximately has equivalent properties to a Metric grade 8.8.

Hope this helps.