Getting the JK’s front end working properly – Part 2…. .
As per my last monologue I’m still working on my JK’s front end. Just as a refresher it’s a 09 manual Rubi shorty currently with 35’s.
The current front end mods are Poly Performance high clearance lower control arms, MOPAR cam bolts ( which aren’t necessary any more but…… ) , very long sway bar links, +40mm springs and the longest OME shocks.
As I explained last time, I was after better handling ( it was a bit squirrely with lift and stock arms ) - ended up achieving this by fitting the adjustable lower arms, as well as getting extra droop travel. Wasn’t expecting any change in ride quality – so that was a bonus.
Initially I wasn’t really interested in adjustable top arms – lower ones would get the castor back within limits so why bother? However I was pleased with the improvement from the bottom arms so was on the verge of getting adjustable top arms as well – even if I wasn’t quite certain just what they would fix.
As I was lying underneath - pondering the front suspension ( weird I know, but it was warm outside and pleasant lying on the lawn ) I noticed that there was much more adjustment available on the Poly lower arms than I was using…. In fact the adjusters weren’t anywhere near mid way… what gives?
It then struck me ( no - not the lower arm ) that as I had lift, the arms were no longer level with the chassis and therefore had moved the front axle back slightly - the change in arm angle effectively causes the axle to pivot backwards in an arc.
With only adjustable lower arms you can get the castor right ( a big plus ) but you can’t allow for the changed arm angles. By fitting adjustable lower and upper arms, assuming they have the correct length adjusters, you can fix the caster and compensate for the lift - mystery solved ! Getting the axle back in line with the panhard and drag link can only help the steering and handling. That's my theory anyway.
So…… as I was happy with the Poly Performance lower arms it seemed logical to follow suit with the uppers. Emptied the JK’s piggy bank again and shot off an order to Double Black Offroad – where I’d got the lowers.
Fitting them
Well, it should be no big deal ( the lower arms were easy ) so the “mate” got conscripted again, and we got it underway….. That’s when the #$%^ Jeep design gremlins really took their revenge.
The drivers side - upper arm - rear bolt can’t be removed without dropping the exhaust pipe off the manifold ( can’t speak for a diesel ) – it hits dead centre of the pipe. What the hell were Jeep thinking ? If the bolt had been inserted from the outside ( there’s even a cutout in the chassis to make this possible ) it would be dead easy – but no it has to be the hard way.
Getting the pipe of the manifold wasn’t fun either as the cat converter / heatshield means you can’t use a socket ( @#$% Jeep! ) – you have to undo the manifold flange bolts a fraction of a turn a time – a curved, short ring spanner works well ( 16mm IIRC )…… oh well. A bit of CRC on the threads helped and fortunately the bolts don’t require lots of turns to remove.
This is absolutely nothing to do with the Poly ( or any other arms ) design – you can’t get the stock arm off with the pipe on – let alone fit anything else.
Apart from that little Jeep “design” @#$% up, fitting the Poly Arms is dead easy – say 20 minutes to drop the exhaust off the manifold, 30 minutes to fit the upper arms and another 15 minutes to put the exhaust back on again. It just seemed longer as the bolt stupidity got me pissed off. Needless to say the “problem” bolt went back in the other way around in virtually no time.
Having someone to assist pays off when your putting the exhaust back on. If they lie underneath and push the pipe up, it makes it so much easier to get the bolts started.
If you have a Rubi, the wiring to the diff lock is attached to the front of the passenger’s side upper arm. Carefully snip off the plastic clip THEN remove the arm. A cable tie can be used to tie the wires onto the new arms,
Oh – and forgot to mention last time that the lower ( and upper ) Poly arms have “pinch bolts” to lock the adjusters in place after the alignment is set - make sure they are tightened. Adjustment is good… but not whilst your driving !
So what’s the outcome?
Small improvement to the ride IMO and also seems better on road with the axle back where it should be – and with the right castor.
So whilst the top arms don’t produce as significant an improvement as the lower arms there’s certainly a good engineering reason behind fitting them. Sort of the icing on the cake – so to speak.
__________________
It seemed like a good idea at the time........
|
