How much to tighten up rear u bolts?

[benwall101]

Hi just fitted new rear u bolts with the lowering blocks from ESM does any body know how tight there ment to be tightend up too?

Thanks Ben

[bmcecosse]

Lowering blocks are a big mistake.......how much clearance do you have from the bump stop to the chassis? The U bolts need to be firmly tight - but only tighten with the weight of the car on the suspension.

[mike.perry]

Maybe if you have fitted 7 leaf Traveller springs to a saloon then lowering blocks would be useful

[chrisryder]

Indeed. I have 7 leaf springs and lowering blocks on my saloon. Looks and drives a treat.

bmcecosse. I'm curious as to why you suggest tightening the u-bolts when the suspension is loaded? With the wheels on the ground, the u-bolts are in tension, making it very difficult to tighten the nuts.

[MarkyB]

They have lock nuts so won't be going anywhere, do them up with the appropriate spanner working round them so they are all equally tight.
After the car has been in use for a week or so I'd revisit them and check if any bedding in has occurred necessitating another nip up.
The bushes at the ends of the spring need tightening with the car on the ground, I don't think this applies to the U bolts.

[Alex'n'Ane]

Indeed. I have 7 leaf springs and lowering blocks on my saloon. Looks and drives a treat.

bmcecosse. I'm curious as to why you suggest tightening the u-bolts when the suspension is loaded? With the wheels on the ground, the u-bolts are in tension, making it very difficult to tighten the nuts.

Why does that make it difficult to tighten the nut? Your not turning the bolt.. And I found that if tightened up the air they were over tight, and the bushes squashed up too much, making the back end skittish.

[bmcecosse]

Simply because the suspension will all be 'in place' - yes it will be hanging on the bolts - not a problem.

[chrisryder]

Indeed. I have 7 leaf springs and lowering blocks on my saloon. Looks and drives a treat.

bmcecosse. I'm curious as to why you suggest tightening the u-bolts when the suspension is loaded? With the wheels on the ground, the u-bolts are in tension, making it very difficult to tighten the nuts.

Why does that make it difficult to tighten the nut? Your not turning the bolt.. And I found that if tightened up the air they were over tight, and the bushes squashed up too much, making the back end skittish.

You've got the hole weight of the back of the car on the 8 nuts. Increasing friction under the heads of the nuts.

I once had a knocking from the rear. Thought it could be loose u-bolt nuts, but wiggled underneath to tighten them. They were pretty damn tight. I then jacked up the body and found the axle to be very loose. Only then could I tighten the nuts further to stop the knocking.

The rubber pads are only there to reduce vibration from the axle transmitting to the body. Surely? Being 'too tight' wouldn't make it skittish, but reduce compliance and reduce axle tramp and increase response. You can get poly ones for a reason.

[Alex'n'Ane]

Sorry please ignore my post! I misread it, and thought we were talking about the rear shackles!! My mistake. I'm with chris on this one now..

[chrisryder]

Huzzah!

one of us... one of us...

[bmcecosse]

Seriously - with oiled threads - it's not a problem to tighten the nuts sufficiently...... But obviously they should be tightened little by little - round and round the square.......

[benwall101]

^
shouldnt you tighten the nuts diagonaly? - thats what i was always told

[les]

You were told rightly, the reason being to avoid distorting things.