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Rear Spring Position

Posted: Mon Apr 30, 2012 5:49 pm
by oddbod
Our Saloon passed its MOT today HOOORAAAAY!!!!!!!!!! :D :lol:
I changed the rear bushes,shackle pin and shackles for the MOT,but I am unsure as to the position of the rear spring,on our Saloon the rearmost part of the spring,on both sides seems to be touching the chassis,is this right or should I get longer shackles to increase the clearance?

Re: Rear Spring Position

Posted: Mon Apr 30, 2012 6:31 pm
by bmcecosse
Well done with MOT and no - it's not normal. Longer shackles are an answer - easy to make yourself! How much clearance is there between bump stops and chassis rail pad?

Re: Rear Spring Position

Posted: Mon Apr 30, 2012 6:49 pm
by oddbod
I'm not quite sure of the relevance,but I can fit 2 fists,one atop the other in the gap. I think the issue may be that a new rear chassis hanger has been welded in and the rear of the spring is rubbing,and on the other side,when the car was "lowered" the chassis was rubbing on the spring all the time and has distorted. On one side the spring is rubbing on the new chassis piece,and on the nearside very close to rubbing. I have only just discovered this as I took it for a shake down before the MOT and noticed "noises" from the rear and began to recheck my bolt tightening after renewing the bushes and pins.

Re: Rear Spring Position

Posted: Mon Apr 30, 2012 7:08 pm
by bmcecosse
Two fists sounds extremely high already........ 2" would be considered excellent..... Do you have full height bump stops??

Re: Rear Spring Position

Posted: Mon Apr 30, 2012 8:40 pm
by oddbod
It looks as if the bump stops may have been "shaved" when the car was lowered previously,but at the moment the problem is with the pivot action at the rear of the back spring,there is contact between the spring where the pin is and the chassis,the nearside is only a couple of millimetres from contact and I would prefer more margin of clearance as the car is going to be heavily loaded quite often!

Re: Rear Spring Position

Posted: Mon Apr 30, 2012 9:27 pm
by oddbod
I've just looked at LOADS of photos of Moggie rear Shackle/Spring arrangement, mine has almost no clearance on one side between spring eye and shackle pin, and on the other side is touching, I would estimate the gap on others I have looked at is a good fat finger and then a bit more!! I think a chat with our Racing Specialist may throw light on longer shackles!! ( I need to order some fancy bits anyway,so at least I can claim a safety angle on the expenses :wink: )

Re: Rear Spring Position

Posted: Mon Apr 30, 2012 9:52 pm
by bmcecosse
But it seems to be sitting too high as it is........ I suspect a problem with the positioning of the spring mounts........ Longer shackles will hopefully give you some clearance - but the car will be ridiculously high........ Shackle plates can just be flat bar 5/16" thick with holes drilled. Increase the distance between the holes by 1" will lift the car 1/2". Don't go any longer than that.......

Re: Rear Spring Position

Posted: Tue May 01, 2012 7:17 am
by kennatt
well don;'t know how its been lowered but spring touching the chassis is the classic sign of springs that have flattend out due to age,which makes them longer hence the touching chassis,but usually accompanied with bump stop also on or close to the chassis,New springs are the usual remedy but longer plate as bm says would also work,but if it is the springs then beter to renew.

Re: Rear Spring Position

Posted: Tue May 01, 2012 9:31 pm
by linearaudio
This has come up in the past, where the front pivot points of the springs have been re-welded in the wrong place during anti-rust surgery. First determine the gap from a standard set of bumpstops on your axle and the chassis. As BMC says, sitting normally 2" is a good gap, only likely to decrease with age :( . If you have this sort of gap, and your rear eyes are hitting the chassis, then the culprit is almost certainly wrongly located front pivots. Someone, somewhere, sometime led a thread where his were so bad that the prop shaft wouldn't mate up and also locate in the back of the gearbox!! At that time there were some reference dimensions bandied around to check the front mount position, but the source of those may no longer be available... i think the dimension was from the front pivot centre to the rear shackle chassis hole centre(makes sense!). Will try to dig it up for you!

Re: Rear Spring Position

Posted: Tue May 01, 2012 9:39 pm
by oddbod
Thanks for the info linearaudio, I am sure that the bump stops have been cut down to "lower" the car before I got it, as I removed some "blocks" from the area of the u bolts on the suspension, I am pretty sure that better springs would be a good thing to put on the car, I am not in a position to buy new springs, but could make longer shackles quite easily and cheaply, I have put an ad in the Wanted section on here and will fit if I can find an affordable, better set. At the minute the springs are in contact with all the welding I had done for the MOT,so will cause major problems without a fix quick!! Another excuse to mess with the car I suppose :D

Re: Rear Spring Position

Posted: Tue May 01, 2012 9:54 pm
by bmcecosse
Make up the longer plates - it only takes minutes and you will see the effect right away.

Re: Rear Spring Position

Posted: Tue May 01, 2012 10:20 pm
by oddbod
Just to clarify BMC, the "2 fist" measurement is between the top of cut down bumpstops and the pad up in the rear wheel arch,is this the "chassis rebound pad" of which you speak? I have no way of telling at the minute how much has been cut off the bumpstops, as I have nothing to compare to until tomorrow when I can peer under a traveller, but I fear the bumpstops on that may have been mangled too!!!

Re: Rear Spring Position

Posted: Tue May 01, 2012 10:24 pm
by bmcecosse
Standard bump stops stand about 4 inches high..... and 2 " above that would be considered 'high'. My stops are cut down to 3" - and I am lucky if I have 1.5" clearance above them - and they are relatively new springs. Mind you - I do carry a box of spares in the back......

Re: Rear Spring Position

Posted: Wed May 02, 2012 9:02 am
by oddbod
Oh, well my bump stops are not much bigger than front new ones!!!! :o