Stop the Bump

[silloyd]

Had a creaking noise on the rear offside suspension...that, on investigation, turned out to be a broken spring

It broke where one of the bands has worn the leaf through over time:[frame]
(that's the front pivot in view)
[/frame]

Comparing the old spring with the new, it's clear to see the degradation over 44 years and why the back end was sitting so low:[frame][/frame]
(Spot the missing band on the unbroken left side)

I was lucky that the problem manifested itself as as creak and not a catastrophic failure!! and no wonder that the clearance above my bump stop was only about 1/2" - 3/4" prior to the 'creak'!

Anyhow, in the process of replacing pretty much everything to do with the rear springs (because it was all cream crackered) my attention turns to the bump stops.

Message board wisdom suggests that even with new springs it is wise to reduce the bump stop length, by as much as 1.5". However this seems a lot considering the standard length is only 3".

I get the point about keeping the profile, i.e. progressive rate, but how much should I reduce the length by and has anyone got any pictures of their adjustments' please?

[les]

Would you mind telling me where you got your new spring from please?

[bmcecosse]

If in doubt =just cut say 1/2" off at first and see how that goes. The TOP tip is to drain the dampers and flush/refill with SAE 40 oil. I promise you , you won't be disappointed with the huge improvement in the ride !

[DAVIDMCCULLOUGH]

Not nice, I had a spring break on the traveller coming off the Liverpool boat on the way to the National rally one year. I wondered why the car felt floaty though didnt stop for about 50 miles, only to discover the wheel had moved back by about 1 1/2' and it was only the spring bands holding it together.........

There are usually only 3 bands fitted so I dont think your old one is missing one.

[silloyd]

Thanks for the replies

Would you mind telling me where you got your new spring from please?

They came from ESM.


BMC - have flushed the dampers and refilled with SAE40, having read previous posts. (I'd used SAE30 before so will be interested in any notable difference). May just try 1/2" first as it looks feasible to cut them in situ.

There are usually only 3 bands fitted so I dont think your old one is missing one.

Understood, was basing my view on the new spring. Were the originals 'handed' then, i.e. with the missing band at the back?

[philthehill]

The minor rear spring was originally fitted with three clamps - two forward of the axle and one to the rear of the axle.
Section I.1 Fig 1.3 of Minor wksp shows the Minor rear spring fitted with the two spring clamps fitted to the spring forward of the axle and it does state that "the spring must be replaced with two spring clamps forward of the axle" in the text of Section 1.1.
The two spring clamps forward of the axle do two things;-

1.....They keep the spring leaves aligned.
2.....The help eliminate axle tramp.

With only one spring clamp to the rear of the axle the spring is allowed to flex more than the front half of the spring and therefore assist in providing a comfortable ride. So with two spring clamps to the rear of the axle the spring would not be as flexible as originally designed and the ride may be a bit stiffer and probably harsher.

[frame][/frame]

[bmcecosse]

The replacements these days all seem to come with 4 clamps. A bit safer I suppose in the event of a break in the main leaf, and no need to worry which way round to fit the thing.

[silloyd]

The minor rear spring was originally fitted with three clamps - two forward of the axle and one to the rear of the axle.
...
With only one spring clamp to the rear of the axle the spring is allowed to flex more than the front half of the spring and therefore assist in providing a comfortable ride. So with two spring clamps to the rear of the axle the spring would not be as flexible as originally designed and the ride may be a bit stiffer and probably harsher.

Thanks for that explanation. I think I'd prefer the 'bit stiffer' (sprung!) ride, given that I've been mostly on the bump stops for some time, so I'm not minded to remove a clamp - though I could do so later with the spring in situ, if it appears to be a problem.

[les]

Thanks for the supplier details, looks like they are selling springs with the proper clamps rather that the ones using packing case straps and a piece of rubber!

[silloyd]

That's the case fro the 7 leaf Traveller springs that I bought but can't say for the other types - worth a call before ordering, I've always found them to be very helpful.

[les]

Well it's a bit late for me this time round, I had to make my own clamps to substitute the half hearted ones that were on the springs I bought but handy to know the proper ones seem to be available now.

[mike.perry]

Would Jubillee clips do??

[bmcecosse]

No. Not nearly strong enough.....