revilla Posted May 10, 2015 Share Posted May 10, 2015 With a friend rocking the car side to side by the roll bar, how much lateral movement is expected / acceptable in the A-frame bush? i.e. visible side to side movement along the axis of the bolt of the de Dion relative to the A-frame. Link to comment Share on other sites More sharing options...
6speedmanual Posted May 11, 2015 Share Posted May 11, 2015 Very little! There is only about 1mm clearance on either side before it stops out on the bracket on the deDion tube. Sometimes there will be race shims filling this clearance. Is the nut and bolt tight? They have been known to work loose. Link to comment Share on other sites More sharing options...
revilla Posted May 11, 2015 Author Share Posted May 11, 2015 Hmmm ... that's what I thought.A friend's car was making a single clonk turning into corners and so I suggested we had a look at his A-frame bush. Whilst he rocked the car, I could see may 2mm movement. So we compared to mine, thinking that mine might be a lot tighter ...There was about 8mm side to side movement! I've been chasing a knocking noise at the back for years. It's been into Nick Potter who said the bush looked fine to him, maybe it's got worse since but the knocking is still the same and it sure don't look OK to me. Not been able to see that level of movement before as I'm generally working on the car alone and it's hard to rock the car and look at the bush at the same time. The bush seems to be badly contaminated with diff oil, which I guess has eaten the rubber. I pointed this out to Nick a couple of years back and he put a pigtail on the breather but it still seems to blowing a bit out for some reason, so will investigate further.Funnily enough I don't get any kind of clonking on corners, it's rough road surfaces and bumps. Had multiple threads on here and tried about everything else, the annoying thing is that bush was the first thing I suspected but not worried about it since Nick signed it off as "like new".I will check the bolt is tight. For one reason or another, there is certainly very poor control of the position of the de Dion to A frame joint. Hopefully I've found the noise at last.So just to be clear - if the bushed joint slops around by a total of 8mm I can pretty much assume that the bush has had it?Thanks. Link to comment Share on other sites More sharing options...
revilla Posted May 11, 2015 Author Share Posted May 11, 2015 OK - just see this thread. Not sure why I missed it before.Looks like I need a new bush. More to the point, I need to solve the problem of the diff oil getting onto it first or the new one will go the same way. Link to comment Share on other sites More sharing options...
Grubbster Posted May 11, 2015 Share Posted May 11, 2015 If you have a BMW diff you should make sure the clonking isn't the dedion tube hitting the diff. Link to comment Share on other sites More sharing options...
revilla Posted May 12, 2015 Author Share Posted May 12, 2015 @Grubbster - No it's a Sierra diff. There are no witness marks on the de Dion or diff. Thanks for making the point though I think from the video below it's pretty obvious where the noise is coming from. This is with a colleague just gently rocking the car from side to side. Even with the shocks and Watts link arms disconnected, pulling the de dion tube around didn't give the impression of anything being wrong here. The problem is I usually work alone on the car and it needed two pairs of hands to reveal it, one to shake the car from the top and me watching underneath. Hard to imagine how I missed it really! The thing that surprises me is that apart from the knocking over bumps, there were no obvious other symptoms. I would have expected the car to have been wandering around on the road and clonking around corners. I would also have expected it to have been picked up on either of the two MOTs it's been through since the noise started! Link to comment Share on other sites More sharing options...
Molecular--Bob Posted May 12, 2015 Share Posted May 12, 2015 Are you sure the bush has failed? Looks like the bolt needs tightening to pull the two a-frame halves together. If the bolt will not tighten, then check that it is the correct bolt, or that the thread isn't damaged.You don't want to get into changing the bush if you don't have to as it ia a proper pain in the but to change it. Just found this on line that shows how close the a-frame bosses should be to the centre mount.http://website.lineone.net/~dmch2/dd_below.jpg Link to comment Share on other sites More sharing options...
CharlesElliott Posted May 12, 2015 Share Posted May 12, 2015 I agree that it looks like the A-frame to DeDion bolt is not done up. Link to comment Share on other sites More sharing options...
CharlesElliott Posted May 12, 2015 Share Posted May 12, 2015 65Nm if I remember correctly.... Link to comment Share on other sites More sharing options...
revilla Posted May 12, 2015 Author Share Posted May 12, 2015 Well it's either tight, seized or the wrong bolt altogether. I tried to tighten it up before driving it home last night and was properly done up. I have found more things wrongly assembled on this car than I have time to list. Link to comment Share on other sites More sharing options...
2GBR Posted May 12, 2015 Share Posted May 12, 2015 As above have stated and it looks like its the wrong bolt and has been wound to end of its threads hence will not tighten further Link to comment Share on other sites More sharing options...
Ian Mackenzie Posted May 12, 2015 Share Posted May 12, 2015 Looks like it needs a good look over. If it's the right bush and it's not deformed there still should not be that much play....then my concusion would be a bent A-Frame ....even if tightened that it a lot of stress to pull it in 8mm....So I'd double check that it is the right bush and it's condition is OK, if yes then I'd go for a new A-Frame.....CheersIan Link to comment Share on other sites More sharing options...
revilla Posted May 12, 2015 Author Share Posted May 12, 2015 OK so tonight I took it apart for a look.The bolt was tight. It has plenty of thread to allow the nut to clamp the A-frame ends.The A-frame is not bent. With everything dismantled, the cups at the ends of the A-frame rest closed up to the inner metal tube of the bush.The bush didn't look obviously unhealthy, although I'm not really sure how to test. With a metal bar through the central tube of the bush I could flex it around a bit but it wasn't obviously in pieces or anything.HOWEVER ... there were additional washers inserted between the inner tube of the bush and the A-frame cups which are not shown in the build manual. There were the optional nylon "race" washers which were knackered (as in the central hole had chewed out leaving just the outer part as a ring) and there were additonal steel washers too.So I cleaned everything up and reassembled without the washers, dropped the weight back on the wheels and torqued the bolt up to 65Nm. The amount of thread showing through the nut had increased only by about the thickness of the washers I had removed, suggesting that the bolt was previously tightened. I then tried rocking the car side to side again watching the bush.There was less movement (maybe 1.5-2mm to either side, 3-4mm in total), however what is clear is that the only thing which is limiting the movement is the point where the A-frame cups hit the de Dion / bush outer tube. The bush itself is soft and compliant enough to allow the joint to move laterally quite easily when rocking the car side to side. The only reason it was moving so much before was because the additional washers spaced the cups away from the central bush and allowed more movement before they hit.So now I don't know whether this suggests that the bush has gone soft an sloppy or whether the bush is fine and the whole thing just looked a lot worse because of the extra washers allowed more movement before large metal parts met. The bush was very oily from differential oil and I believe that this is known to attack the rubber used in these bushes and shorten their lives.I'm beginning to wonder whether this is actually the cause of my knocking noise at all ... haven't managed to test drive it yet to see if anything has changed but will when I can get a chance.Any thoughts? Can anyone else have a quick look to see how much movement their bushes allow when rocking the car side to side for me?Thanks. Link to comment Share on other sites More sharing options...
revilla Posted May 12, 2015 Author Share Posted May 12, 2015 Further update ... been for a test drive, and ...It's WORSE ... A LOT WORSE.Before it clanked when the wheels ran over say a slightly sunked drain cover. Now it knocks and clanks over every slight lump and bump in the road surface. In addition, rocking it side to side in the garage now induces a similar knocking noise which I wasn't getting before and as far as I can tell, the sound appears to be coming from the cups of the A-frame knocking on the de Dion bush boss.Tonight, all I did was jack it up, remove the bolt from the bush, clean and degrease and reassemble without the additonal washers. Torqued up with the weight on the wheels. The fact that this has exacerbated the problem suggests that something I've disturbed (i.e. the bush and fittings) is indeed the source.So without anything else to compare it with, my working hypothesis is: The bush is knackered / gone soft / possibly even torn internally and allows the inner steel tube to slop sideways too easily. Additional washers had been fitted which increased the clearance and reduced the tendency to knock a bit, requiring a bigger bump to displace the joint enough to knock. These would also have allowed more movement before being limited by the A-frame cups and may have contributed to the bush failure by flexing it further. Removing the additonal spacing washers has left the cups closer to the boss and so it knocks over smaller bumps. Optional nylon "race" washers were installed which tended to cushion the contact between the A-frame cups and the de Dion. Rocking it by hand wasn't enough to produce an audible knocking with these in place but it is witout the cushioning of the "race" washers removed you can hear it knocking when rocking it.I would really appreciate it if anyone could look at their car, preferably an Imperial SV from a similar vintage (2003) but I guess all post-1996 de Dion cars will share the same bush arrangement, and tell me: Approximately how much lateral movement can you see in this bush when rocking the car (firmly, but not aggressively)? Are you able to cause it to move enough to bring the A-frame cups into contact with the de Dion tube with just firm manual rocking?I have no previous experience of looking at this bush and nothing else to compare it with.Any further thoughts very much appreciated,Thanks,Andrew. Link to comment Share on other sites More sharing options...
Molecular--Bob Posted May 12, 2015 Share Posted May 12, 2015 There have been 2 designs of bushing for the tube, the first involved 2 halfbushes, the second the metalastic bush,and i dont know when this changed, just wondering if you have the wrong bush type fitted. I had to change to the newer style bush when I had a replacement tube fitted as the housing shape is different. Just looked at my tube fit and i would say that stationary I have less than 1mm each side, and not able to see movement when rocking it. Link to comment Share on other sites More sharing options...
2GBR Posted May 12, 2015 Share Posted May 12, 2015 Perhaps an SV without an SV a frame then if they are a different width from S3 Link to comment Share on other sites More sharing options...
CharlesElliott Posted May 13, 2015 Share Posted May 13, 2015 Andrew - I suspect 1, 2 and 3 all apply in your case. Knackered bush, attempt to stop knock etc.I would replace the bush and go from there. Link to comment Share on other sites More sharing options...
CharlesElliott Posted May 13, 2015 Share Posted May 13, 2015 One of these maybe. Link to comment Share on other sites More sharing options...
revilla Posted May 13, 2015 Author Share Posted May 13, 2015 @Molecular--Bob: Thanks for checking. I think they changed in 1996 in which case I should be using the later matalastic bush - which is what looks to be installed. It is clearly nowhere near as firm as yours. I think it's just had it. Will get it changed and see what happens.@CharlesElliott: Yes, have to agree, I think the bush has gone and somebody has tried to bodge it.So ... after removing the "bodges" ... Ladies and Gentlemen, after two years of searching, multiple false starts and blind alleys, many threads on here, many attempts to describe the noise to people and much (very gratefully appreciated) help from many members on here, allow me to introduce ... <drum roll> ... THE BLOODY AWFUL NOISE I'VE HAD TO PUT UP WITH EVER SINCE I'VE OWNED THIS CAR (which I can finally reproduce in the garage rather than just on the road): Link to comment Share on other sites More sharing options...
revilla Posted May 13, 2015 Author Share Posted May 13, 2015 Only just noticed looking back at my own video - does rather look like somebody has been at the boss on the de Dion tube with a hammer, doesn't it? Maybe gave up trying to whack it out so bodged it? Link to comment Share on other sites More sharing options...
Smithy77 Posted May 13, 2015 Share Posted May 13, 2015 Ahhhh, it all makes sense now! It was good to 'help' you find the culpret on the weekend. Definitely one of those 'I was there' moments.... Link to comment Share on other sites More sharing options...
Molecular--Bob Posted May 13, 2015 Share Posted May 13, 2015 Even though mine doesn't seem to move, what is the life expectancy of this bush in road use? Mine was done by the 7-Workshop as part of the repair work after it was stolen, which I think was about 7 years ago. Link to comment Share on other sites More sharing options...
CharlesElliott Posted May 13, 2015 Share Posted May 13, 2015 You have the fun of trying to get that bush out (and the new one in) now.... Link to comment Share on other sites More sharing options...
SM25T Posted May 13, 2015 Share Posted May 13, 2015 Mine hasn't been changed in the 8 years I have owned the car. May well be original 13 years old and 75k miles ? Link to comment Share on other sites More sharing options...
Grubbster Posted May 13, 2015 Share Posted May 13, 2015 I recently changed mine - a 2003 car that has probably >25000 miles, many on track. I did is as a precaution (when I had the car in bits) but I don't think there was anything wrong with it. A right bugger of a job, I took a saw to it to get out and then ended up taking it elsewhere to have the new one fitted. A lot of effort. I wish I hadn't bothered! But yours is shot so you have no choice! Link to comment Share on other sites More sharing options...
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