Rear Trailing Arm Bush freeplay - thoughts on this install
Hi all,
I picked up a dc2 few weeks ago, have been working through fixing up a few things. While checking the rear end I inspected the RTA bushes.
A previous owner had installed some polyurathane RTA bushes - I thought this was a good thing until closer inspection.
Passenger side is upside down (the "top" marking is facing downwards), but are they in back to front as well, there is at least 2mm free play b/w the washer and the bush as shown in this pic. Anyone have similar poly bushes and can comment on freeplay/orientation?
Both driver and passenger have the same amount of clearance to the washer and there are some clunking sounds which I believe are caused by this.
Never mind the white in the pic, I sprayed them with lithium grease before I saw the freeplay.
I picked up a dc2 few weeks ago, have been working through fixing up a few things. While checking the rear end I inspected the RTA bushes.
A previous owner had installed some polyurathane RTA bushes - I thought this was a good thing until closer inspection.
Passenger side is upside down (the "top" marking is facing downwards), but are they in back to front as well, there is at least 2mm free play b/w the washer and the bush as shown in this pic. Anyone have similar poly bushes and can comment on freeplay/orientation?
Both driver and passenger have the same amount of clearance to the washer and there are some clunking sounds which I believe are caused by this.
Never mind the white in the pic, I sprayed them with lithium grease before I saw the freeplay.
Top marking should be on top because usually it has thinner bushing than bottom side. As for side to side play, I think this is how they designed it for pedders bushes.
I'm not sure why pedders bushing can go side to side where oem counterpart is firm no play.
S P A M | W O R K S
With our special rotational tires, it will allow you to drive very fast. - JK Tyre
Top marking should be on top because usually it has thinner bushing than bottom side. As for side to side play, I think this is how they designed it for pedders bushes.
I'm not sure why pedders bushing can go side to side where oem counterpart is firm no play.
Seems strange to me. I think it is a nolathane part, it has 6179 stamped on it which I found on this page.
The install instructions from their page mentions 2 washers, I looked on the inner side and the circlip does not look to have a washer between it and the bushing. I'll email nolathane now that I've found it.
I only noticed the noise after fitting the hardrace rear camber arms, but they're all done nice and tight so I'm confident that the noise isn't coming from them, can't see any other signs of contact around the suspension and have removed the rear anti roll bar to troubleshoot.
I greased all the rear bushings at the same time as fitting the camber arms, so I think the RTA bushes are more free to move laterally than before greasing causing the knocking.
The install instructions from their page mentions 2 washers, I looked on the inner side and the circlip does not have a washer between it and the bushing inner steel tube. I'll email nolathane now that I've found it.
I only noticed the noise after fitting the hardrace rear camber arms, but they're all done nice and tight so I'm confident that the noise isn't coming from them, can't see any other signs of contact around the suspension and have removed the rear anti roll bar to troubleshoot.
I greased all the rear bushings at the same time as fitting the camber arms, so I think the RTA bushes are more free to move laterally than before greasing causing the knocking.
ah ok, i thought they were pedders cos had same replacement installed when i purchased a car and they said was pedders.
ive had knocking sound after installing spc rear camber arms too in EG. noise is gone after went back to stock camber arms.
i was sure all bolts were tight too.
S P A M | W O R K S
With our special rotational tires, it will allow you to drive very fast. - JK Tyre
ah ok, i thought they were pedders cos had same replacement installed when i purchased a car and they said was pedders.
ive had knocking sound after installing spc rear camber arms too in EG. noise is gone after went back to stock camber arms.
i was sure all bolts were tight too.
right, suppose the clunk/knocking could be the camber arms. Given that they have rubber bushes it just didn't seem as likely once I saw the RTA bush free play, I'll have to take the passenger RTA bush out regardless since it is in upside down. I'll get a better look once it's out, have to do all the RLCA bushes anyway so looks like I'm in for some fun.
quite a few aftermarket rta bush allow the shaft to slide side to side but if I understand correct he means theres some gap between the shaft and bush which could make sound I reckon
OP can you take a better angle pic of the freeplay gap?
Yes, that is the gap I'm talking about. Seems like it would be unpredictable if that is by design.
I can't feel any play between the shaft and the bush radially checking by hand. Also the circlip on the back I would think should have a large washer between it and the bush which it doesn't.
There is possibly a smaller washer wedged in the other side between the circlip which I initially thought was a steel inner tube, hard to see without taking it out. I'll have another look tomorrow and try to get a pic of the inner side.
Due to the design of the rear there isnt really much side motion in that bush,it takes more of a twisting force
as I said before,some even have the shaft totally freemoving in the bush
also you have spherical ones for track but there is a bit of mystery as to which is ideal
I have a feeling making that bush too rigid isnt a good idea as it effects the entire strut motion,Im not an expert this is purely my guessing
we need an engineer to chime in about this
In bump travel there will be some lateral movement at the bush, so I think there should be some play in the shaft especially with the solid style bushings, it seems excessive in the nolathane style which has voids for compliance though.
I can change the camber arms back to stock to check if they are the cause of the knocking.
Spoke to nolathane tech support, they said the design is supposed to be floating and it shouldn't really matter with the freeplay. They also said the circlip doesn't even need to be there on the back and was only added as a safety requirement by NZ road authority. Could be the added camber with the hardrace kit is causing the RTA bush to behave a bit differently and causing the noises.
I will try putting some rubber washers in the gap to see if the noise disappears, if it is the source then at least I know what it is.
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Originally Posted by rc_
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