Hybrid_From_Hell Posted December 23, 2009 Share Posted December 23, 2009 Hi All, Working on mates LR90 has seen me post here about probs still has, now I drove home in mine thinking gawd I have a lesser version : http://forums.lr4x4.com/index.php?showtopic=50616&pid=457448&st=0entry457448 So, I really don't know much about either caster correction arms noe Double cardon props other than knowing what they look like, so please to the experts here with user knowledge (not "GQs" - Google Queens ) please can you educate me and maybe others here. I guess what I would love to know is Caster Correction arms / Bushes How do you know if you need them ? What if you need them will you suffer without having them ? How much correction for how much lift ? How o you actually calculate what lift you have ? Whats the difference between Caster correction arms and bushes Are there downsides to having either of them ? Anything else of interest / worth knowing ? Double cardon props What LR have them as standard ? If so why ? Are the 3 UJs the same sizes as the std 2 UJs What other mods are needed whats the OD of them (V8 exhaust clearnace poss probs for moi maybe / maybe not Who makes really good ones ? Which are poor ? Why is a DC prop not out of phase How do they work ? At what lift do you need one ? Is their a correlation between Caster Correxction and DC Prps, or are they 100% seperate ? If not how do the compliment each other ? If say you didn't need one and fitted one what effect may you have ? Why obnly neded on the front of a lifted truck - why not rear too ? Anything else worth knowing ? Sorry for the above, need to bone up on tech fast Discuss Nige Quote Link to comment Share on other sites More sharing options...
Pete Attryde Posted December 24, 2009 Share Posted December 24, 2009 (edited) My understanding and experience is that if the suspension is lifted approx 2" or more you may suffer a lack of self centering / vague steering going in a straight line. This is caused by the angle castor being altered, because the axle will have rolled (lifting the diff pinion) because of the steeper angle of the hockey sticks with relation to the chassis. Jack the front end up on the chassis and watch what the axle does. To cure this lack of self centering you can fit either bushes or corrected arms this restores the castor angle but then can put the phasing of the front propshaft out, causing vibrations at which point you fit a double cardon prop to cure the prop vibration. I have used both bushes (great for a road vehicle but due to the way the are made not very flexible) and castor corrected arms (Britpart as it happens but amazingly they are well made.) both methods cured the steering, both required a double cardon prop. Eventually i have gone back to standard height suspension/props as the U/J's are easier to change and cheaper. I got my double cardon prop from Devon 4x4, but have heard good things about propshaft clinic and Gwynn Lewis's products. HTH Pete. editted to correct stupid school boy error pointed out by Soren Edited December 24, 2009 by Pete Attryde Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted December 24, 2009 Share Posted December 24, 2009 Pete, Castor and king pin inclination (KPI) isn't the same. By fitting castor corrected arms/buches/swivels you won't change the KPI. KPI can be adjusted via your tire diameter, and the backspacing (is it called this?) of your rim. But you are right that both these factors play in on how your car selfcenters. Quote Link to comment Share on other sites More sharing options...
Pete Attryde Posted December 24, 2009 Share Posted December 24, 2009 Soren, You are indeed correct. I had not had enough coffee when I posted. Pete. Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted December 24, 2009 Share Posted December 24, 2009 Soren, You are indeed correct. I had not had enough coffee when I posted. Pete. Guess we all know about this problem ey? Quote Link to comment Share on other sites More sharing options...
steve b Posted December 24, 2009 Share Posted December 24, 2009 another way to deal with castor correction is to redrill the holes in the swivel housing, the drawback is you then have non-std swivels should a replacement be reqd...I have seen lots of castor corrected(fabricated) radius arms break out the rear of the two axle bushs. cheers Steveb Quote Link to comment Share on other sites More sharing options...
Aragorn Posted December 24, 2009 Share Posted December 24, 2009 my 2p: A DC prop isnt out of phase because the double cardan joint is a constant velocity joint. When the two flanges of a propshaft arent parallel, like in the front axle, the shaft doesnt run at a constant velocity, it speeds up and slows down as it turns. The standard prop phasing is intended to cancel out most of this variance and it does so on a standard vehicle reasonably well. The connection with caster correction, is due to the method used. If you fitted caster corrected swivel balls for instance, you wouldnt have the same problem (at least not without getting into mega lifts). By using the arms, you rotate the diff nose in relation to the transfer box, and the standard phasing is now no longer canceling out the uneven running. I suspect landrover used it on the D2 to make it a little smoother and more refined. You can fit a 300TDi defender prop to a D2 with no problems, and one of the members on here (BBC i think?) does just that to customers vehicles when the DC prob fails. The rear doesnt suffer the same issues as much because the rear diff flanges are parrellel to the transfer box as standard, although with enough lift you might end up in the same situation as the axle drops thru an arc. Quote Link to comment Share on other sites More sharing options...
ChrisW70 Posted December 24, 2009 Share Posted December 24, 2009 another way to deal with castor correction is to redrill the holes in the swivel housing, the drawback is you then have non-std swivels should a replacement be reqd. I think I've seen castor corrected swivels for sale on Paddocks website, about 70 quid each I think - bit cheaper than the arms I guess. Quote Link to comment Share on other sites More sharing options...
andyb Posted December 24, 2009 Share Posted December 24, 2009 You could have the axle casing re-jigged and this would leave you with all standard parts for those that you would need to replace as part of maintenance. It would make sense to reinforce the casing and fit some kind of diff protection at the same time. Perhaps the only true fit and forget option Quote Link to comment Share on other sites More sharing options...
nicks90 Posted December 24, 2009 Share Posted December 24, 2009 and the whole issue of steering self centering with a lift is also dependant on many many factors. Some vehicles have terrible self centering, others (mine) dont suffer at all. this can be attributed to how worn your kingping bearings are, how tight you've set the preload, backspace/scrub radius of the wheel/tyre package you fitted amongst others. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted December 24, 2009 Author Share Posted December 24, 2009 ^^^ Q Whats scrub Radius please > Nige Quote Link to comment Share on other sites More sharing options...
Pete Attryde Posted December 24, 2009 Share Posted December 24, 2009 Scrub radius:- Pete Quote Link to comment Share on other sites More sharing options...
Aragorn Posted December 24, 2009 Share Posted December 24, 2009 Its a geometric distance, between the centre of the tyre, and where the line representing the steering axis intersects the road surface, when viewed from the front of the vehicle. It will change with different offset wheels, (and with lowering the vehicle on a car with mac struts or similar, thou that doesnt really apply here) Handy diagram: http://www.rorty-design.com/images/pos_scrub_radius.jpg Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted December 24, 2009 Author Share Posted December 24, 2009 Ah Ok, So "Lifting" won't affect Scrub ?, just castor and UJ Angles ? Nige Quote Link to comment Share on other sites More sharing options...
SteveG Posted December 25, 2009 Share Posted December 25, 2009 I'll educate you Nige, it's Cardan not Cardon!! ;) Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted December 28, 2009 Author Share Posted December 28, 2009 Bowlox, I'm wrong again Anyone know if any LR have them as std ? Ta Nige Quote Link to comment Share on other sites More sharing options...
landroversforever Posted December 28, 2009 Share Posted December 28, 2009 Disco 2 front prop PS: nige... whet ia ot wiv you're sprelling? Quote Link to comment Share on other sites More sharing options...
steve b Posted December 28, 2009 Share Posted December 28, 2009 Stage 1 V8 too Nige, bit rare though Steveb Quote Link to comment Share on other sites More sharing options...
Pete Attryde Posted December 28, 2009 Share Posted December 28, 2009 Disco 2 one needs a different t-box flange and doesn't have much in the way of grease nipples. Pete. Quote Link to comment Share on other sites More sharing options...
reggie Posted January 8, 2010 Share Posted January 8, 2010 & I was just about to buy some castor correction arms or bushes, now I'm not so sure if I should as I can't afford the DC prop at the min. If I did fit them without the DC prop whats the worst that would happen? I can only afford to buy bits here & there. Quote Link to comment Share on other sites More sharing options...
muddy Posted January 8, 2010 Share Posted January 8, 2010 I also beleive that defenders with a sailsbury (or however you spell it) front axle also have a DC front prop, armoured ones etc etc.. Quote Link to comment Share on other sites More sharing options...
ajh Posted January 8, 2010 Share Posted January 8, 2010 Correcting at the axle housing or swivel ball is the only proper way to START fixing things with a lift, as you lift more and more you will run into other issues though but with 2-3" just doing the swivels should solve the issue. Only then fit a DC if you get vibration. Corrected arms are never the correct solution. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted January 8, 2010 Share Posted January 8, 2010 i thought the general consensus was that castor correction is only really needed over a 2" suspension lift? thought that was what you have Reggie? Quote Link to comment Share on other sites More sharing options...
ajh Posted January 8, 2010 Share Posted January 8, 2010 i thought the general consensus was that castor correction is only really needed over a 2" suspension lift? thought that was what you have Reggie? No, it is more that it is only worthwhile when castor is out by more than 2-3 degrees. Given Land Rover tolerances it could be out this much from the factory and lifting it could put it either on-spec or out by 6 degrees depending on how it is out and which way. You really only know by measuring. Quote Link to comment Share on other sites More sharing options...
rocksteady Posted January 8, 2010 Share Posted January 8, 2010 Interesting, this would explane why some do, and some don't. On that thinking I've been quite lucky so far! Quote Link to comment Share on other sites More sharing options...
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