jad Posted April 8, 2019 Share Posted April 8, 2019 Been having a vibration problem on my S3 109 between light load and overrun. Sounds like a bush has gone, gives quite a heavy shorting noise, not felt so much. Having a look at the car the chassis bush on the front left spring had gone. We replaced it yesterday and the bush is obviously getting preloaded on the outside of the chassis rail so the bolt is on an angle. the car does have coil sprung axles converted to leafs. Assuming the spring seat is on square what else could be causing the preload? Is there any natural twist to the springs? Could I have them on the wrong sides? Any ideas would be appreciated! Thanks Jad Quote Link to comment Share on other sites More sharing options...
Gazzar Posted April 8, 2019 Share Posted April 8, 2019 Covering the simple stuff first. Genuine last much better than generic. Was the bolt tightened with the car on the ground, or the axle tightened against the chassis with a ratchet strap to mid shocker? Do you have parabolic springs? Mine went first on the same bush, 109 with cheap bushes. Quote Link to comment Share on other sites More sharing options...
jad Posted April 8, 2019 Author Share Posted April 8, 2019 Unsure on the bush, was fitted by Richards chassis. Would like to think they would fit decent ones... I have just fitted a polybush as I happen to have a set. Originally I think we tightened the bush according to the manual standard ride height. I can't remember if we had to jack the car or ratchet it down. Yesterday we tightened the bush with the car on the ground after bouncing it a little to get it to settle. Standard 1978 springs on the car as far as I am aware. Could probably do with a refresh. They were cleaned up a few years ago during the rebuild. Cheers Jad Quote Link to comment Share on other sites More sharing options...
Gazzar Posted April 8, 2019 Share Posted April 8, 2019 I'd hope that Richards would use good bushes. If all else is standard then the most suspect item is the axle, as it's not. Do you want me to put a measure across my front axle, perch to perch? But old seized leaf packs can be hard work on bushes, do they flex at all? If seized then there's a lot of stress going to the bushes. Quote Link to comment Share on other sites More sharing options...
jad Posted April 8, 2019 Author Share Posted April 8, 2019 If you wouldn't mind that would be useful. They seem to flex ok. Think I need to get a ruler out! Cheers Quote Link to comment Share on other sites More sharing options...
Gazzar Posted April 9, 2019 Share Posted April 9, 2019 I'll get a chance this evening, I hope, if work finishes on time. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted April 9, 2019 Share Posted April 9, 2019 Measuring on a series three stage one V8, spring perch bolt hole recess to bolt hole recess, I get 723 mm plus or minus 1mm. It isn't exact, the diff gets in the way! Quote Link to comment Share on other sites More sharing options...
jad Posted April 9, 2019 Author Share Posted April 9, 2019 Cheers! I'll have a measure tomorrow. Jad Quote Link to comment Share on other sites More sharing options...
Snagger Posted April 10, 2019 Share Posted April 10, 2019 I doubt any chassis manufacturer uses expensive bushes - they won't be covered in any warranty as they're a consumable, and when you consider the number they must fit per year, they'd make quite a saving on using cheap parts. You description does sound like a failed bush. It's important that the bolts are tightened with the vehicle at typical weight on flat ground. Strapping the axle to the chassis to compress the springs is fine for getting bolts in, but it has to sit completely naturally for the final tightening or premature bush failure ensues. It is the bush nearest the exhaust down pipe, so that could be a factor, but it seems unlikely that enough heat would get into the bush to cause problems. I suspect it's nothing more than a quality issue. Quote Link to comment Share on other sites More sharing options...
jad Posted April 10, 2019 Author Share Posted April 10, 2019 Exhausts run down the inside of my chassis rails on my V8. The bush had mostly failed on the outside due to the twist. The spacing from centre bolt to centre bolt under the spring looks to be about 734mm. I would say the right is about 180mm from the stub axle and the left about 175mm. The right is on the diff so can't really move so maybe the left needs to come in a bit. I probably need to undo the u-bolts and see where the spring wants to sit in relation to the seat when the tyre is on the ground and the chassis level! Cheers Jad Quote Link to comment Share on other sites More sharing options...
Gazzar Posted April 10, 2019 Share Posted April 10, 2019 Yes, there's a lot you can do with the u bolts. On my lightweight I was able to lose a 1.5cm difference in alignment between the two axles. Ratchet straps are very useful for this, especially if you have two ratchets on the one strap, one on top, one under. Tightening the bolts without a load is acceptable according to the repair manual, they give specifications as to the chassis to axle distance. They recommend using chains, but ratchets weren't common back then. Quote Link to comment Share on other sites More sharing options...
jad Posted April 10, 2019 Author Share Posted April 10, 2019 Only thing is that I have done is use the centre spring bolt as a locator on the seat. Is it ok to drill that out larger so I can move the axle a bit? Quote Link to comment Share on other sites More sharing options...
Gazzar Posted April 10, 2019 Share Posted April 10, 2019 I wouldn't, not yet. It's not reversible. There is some room for adjustment without. Get a genuine bush, loosen the u bolts, get the alignment right, centered and parallel with the back. See how that goes. Quote Link to comment Share on other sites More sharing options...
jad Posted April 10, 2019 Author Share Posted April 10, 2019 Sorry gaz think we are thinking the same thing but my spring seat was made by my dad and I and the hole is a tight fit on the bolt so it won't move about on it... Quote Link to comment Share on other sites More sharing options...
Gazzar Posted April 10, 2019 Share Posted April 10, 2019 Gotcha. Widen away. Don't leave it weak. I think mine had about 2 or 3mm play with original axles and Jones springs. Those perches are cast steel on the series axles. Not casting aspersions on the skill in fabrication, but did you have a pattern to follow? I'm thinking the distance between the axle tube and the spring. Plus double check the pitches are 100% in line parallel and the same distance from the mid line of the axle casing. Just verifying and confirming, because the wear is most likely to come from misalignment. Where else could it come from? Not very likely options, just to spark ideas. Lots of roundabouts? Always run left into the drive? 6 ply tyre on one side, 8 ply on the other? Driving in truck ruts? Are there any other mods? PAS? Steering damper? Worn engine mount on one side,? Quote Link to comment Share on other sites More sharing options...
jad Posted April 10, 2019 Author Share Posted April 10, 2019 A pattern? don't make me laugh 😂 🙈 there could definitely be something out but we did check a lot.... Will try and measure as much as I can when I get some time. This is the problem with projects never done! TVR is coming apart in the garage at the moment. Volvo needs some work on the exhaust. The push bikes are ok at the moment but my knee is having problems 🙄 The landy doesn't do a huge number of miles... Not particularly many roundabouts.... Reverse into the drive... Tyres the same all round and in good condition. It has a P38 steering box and is driven from the Lexus pump that used to run a rack. The steering is light even with a small steering wheel... Engine mounts are both Lexus. There are plenty of modifications..... Cheers Jad Quote Link to comment Share on other sites More sharing options...
Gazzar Posted April 10, 2019 Share Posted April 10, 2019 I know the feeling. Physio for the knees (ACL strength building), Volvo losing charge, or not charging, kit car in pieces in another country, house falling apart (I prefer to think of it as growing bigger), lathe basic training, station wagon in pieces in need of a V8 (not forgotten), a couple of (nice) dry stone wall projects, a sodding flat tyre on the 109. Plus a lightweight rebuild done the hard way. And a day job, teenagers and all the rest. Thinking about it, I realise why I'm knackered all the time! Quote Link to comment Share on other sites More sharing options...
Gazzar Posted April 10, 2019 Share Posted April 10, 2019 How Central (left to right) is the engine fitted? Is the pitman arm ( right name?) on the pas in the correct orientation? It isn't supposed to be in the straight ahead position. Again, just checking. I'll get the mid axle to perch distance for you tomorrow. Quote Link to comment Share on other sites More sharing options...
jad Posted April 10, 2019 Author Share Posted April 10, 2019 Yeah you do not have it easy! Engine is central. Lexus engine mounts fit between the rails with just a bit of spare space. Unsure on the arm will have to check. Icing the knee now 😐 Ta Quote Link to comment Share on other sites More sharing options...
Snagger Posted April 10, 2019 Share Posted April 10, 2019 I would expect the axle to centralise so that any twist in the shackles or springs were equal and the axle slightly offset if the holes locating the spring bolt in the saddles were slightly misplaced, but a weak bush would then tend to take up the error. It's a possible contributing factor. If I understand correctly, you want to elongate that hole to allow the axle to sit centrally and not put side loads on the springs. I think that'd be fine - the location is more important fore/aft. Quote Link to comment Share on other sites More sharing options...
jad Posted April 10, 2019 Author Share Posted April 10, 2019 Yeah that makes a lot of sense and yes that was the idea of increasing the hole size. 👍 It might be the seat isn't completely flat side to side and is twisting the bush but then I would expect to see the same problem on the front bush. Still not convinced this is the problem causing my lift off to overrun noise issue! Quote Link to comment Share on other sites More sharing options...
Gazzar Posted April 11, 2019 Share Posted April 11, 2019 Bushes cause clonk. I think I've a rear bush going, changing direction and lifting off on the pedal causes a noise. Cheap bushes. I'll buy genuine next time. Quote Link to comment Share on other sites More sharing options...
Snagger Posted April 11, 2019 Share Posted April 11, 2019 The only time I had what I understand your symptoms to be was when I installed 1-ton shackles with a standard chassis, which rotated the rear diff pinion axis up and put the prop flanges out of parallel. It's important that each end of a prop shaft is deflected by the same angle unless you have specially phased UJs or a CV/double-cardan jointed shaft. Try measuring your transfer box and diff flange inclinations to check they're all parallel. Of course, if you have fabricated saddles because you installed non-standard axles, you might not be able to set the front diff flange parallel, and may need a couble cardan joint on the front of the prop if your geometry is anything like with the Defender axles on my 109. Quote Link to comment Share on other sites More sharing options...
jad Posted April 11, 2019 Author Share Posted April 11, 2019 Now that's interesting. Entirely possible they aren't completely square. Mine is fitted with 1 ton shackles as well. It does self centre ok but maybe not as much as it should. Assume I could also take the front prop off to confirm? I'm sure the Borg Warner tbox will be ok for a short period without too many beans... Quote Link to comment Share on other sites More sharing options...
jad Posted April 11, 2019 Author Share Posted April 11, 2019 Well the prop is off and I'll drive it to work in the morning. The pinions are at rather different angles.... Snagger on your conversion how close is the steering bar to leaf springs? Quote Link to comment Share on other sites More sharing options...
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