Thread: A-Frame Top Bolt Issue

Sorry for any confusion, these are the 3/4 UNF bolts at the chassis end of the A-Frame

Item #6 in this pic Land Rover Parts - TOP LINK, FULCRUM & BALL JOINT - DEFENDER

Originally Posted by jboot51

Sorry for any confusion, these are the 3/4 UNF bolts at the chassis end of the A-Frame

Item #6 in this pic Land Rover Parts - TOP LINK, FULCRUM & BALL JOINT - DEFENDER

Sorry for dragging up an old post, but what are the specs of these bolts?

3/4 UNF
Length?

I can get some from town but I only have the Defender so cant take out to show them! Doubt they will have imperial anyway but worth a shot I guess. need to order new Superpros now too (because I didn't replace the bolts 12 months ago).

G

4 inch bolt, but the thread will be inside the bracket.
I must have used a 6 inch bolt and cut it down, with a washer either side to get shank all the way through.

Edit that..

Google says..........
Size: 3/4"
Thread: UNF
Pitch: 16 threads per inch
bolt length approx shank length
3" ......... 1 1/4"
4" ......... 2 1/4"
5" ......... 3 1/8"

A 5 inch bolt will have 7/8" more shank which will be the 20mm I was looking for.

Forgive me if I'm wrong, but isn't the clevis supposed to clamp on the inner tube of the bush so that there is no movement of any metal-to-metal components, and the rubber takes all the movement? Then there should be no wear on any components?

Cheers,

Fraser

All I know is I fitted new bushes when I left the UK last year and now they are loose/clunking. So I am going to start again and this time put in new bolts

So you think it should be a tight fit between the bolt and the inner sleeve of the bush?

G

Originally Posted by fraser130

Forgive me if I'm wrong, but isn't the clevis supposed to clamp on the inner tube of the bush so that there is no movement of any metal-to-metal components, and the rubber takes all the movement? Then there should be no wear on any components?

Cheers,

Fraser

All fine in theory, except the standard bolt has too sort a grip length as it's an industrial bolt and so the threads are sitting in one side of the clevis.

Rolled threads are undersized compared to the bolt body, and under load will start to move and deform, leading to the bolt and clevis flogging out.

The crush tube ID is also quite a bit larger than the bolt shank OD, etc. leading to relative movement.
Bolted joints in shear should have little scope for movement anywhere, and should be close tolerance between all surfaces.

Bolts in double shear should not have thread bearing on the clevis.
This is why air frame bolts go up in 1/16" grip (shank) lengths.

Originally Posted by rick130

Mine did the same thing eight years ago, but the clevises were ok. (the steel tube in the bushes were flogged out too)

Replaced the bolts with genuine (much to my dismay at having a thread through the clevis) and used Super Pro bushes, and also wrapped the bolts with shim stock to make up for the small discrepancy between the bolt and new steel bush ID and haven't had to touch them since.

Yes, I'm anal

Me too - you don't remember what thickness shim stock you used by any chance do you Rick?