So I have a 2016 Gt PP1 car. When driving the car the rear end seems to just "wander" around. slow speed (under 30mph) it doesn't seem to do it but anything above that, and especially at faster speeds, its a little un-nerving. I had put the bmr solid bushings in the cradle but that didn't stop it. Where do I need to look for bent or worn stuff to fix this? I have 2 donor cars (im building 2 cars for racing currently) but don't want to do a full cradle/suspension swap if I don't have to. Im using it as a street car now (not a daily) until my client says he is ready to start the build. Car has 117k on it but does everything else fine. Alignment came out perfect as well.
The Mustang Forum for Track & Racing Enthusiasts
Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.
- Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!
2016 GT PP1 Rear End Walking?
- Thread starterAnviltester
- Start date
This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
PatientZero
@restless_performance
What tires are you using. A guy a work with has a supercharged S550 and has said the same thing. I'm curious.
- Thread starter
- #3
have the stock wheels non pp1 car (my pp1 wheels were all rashed up from previous owner and I have 3 cars so swapped wheels). 255/40r19 pzero's on all 4 corners. If I put them on the other cars it doesn't do it - only on this one. It's close to being undriveable at speed. Definitely not confidence inspiring and forget getting on the highway lol
I'm not sure if this'll help or not... but here goes. The S550 rear suspension has a very high level of coupling between camber and toe. If you have a worn bushing on one of the arms, either the UCA or the toe link, it'll cause toe to change as loading on the bushing changes. So, check all the bushings on all the moving parts - UCA and toe link for sure - but if any one of the multitude of bushings back there between the knuckle and the cradle has play in it, it might be the cause of your problem.
- Thread starter
- #5
I will look at all that. Was trying to get a better idea where to look before throwing parts at it or just swapping the whole assembly out for another I have - too much work. Just need to spherical everything I suppose lol. Just trying to get away with the bare min to make it track straight. Is there a difference in the 2016 cradle assembly to a 2018 or 2020 versions or are they all the same (less gear ratios in the diff)?
RES_22
Rob
Check closely the toe link inner bushing....the one in the LCA.
It is not a rose joint...likely worn since you're over 100k miles.
It is not a rose joint...likely worn since you're over 100k miles.
- Thread starter
- #8
pretty sure its all original. Lowering springs added somewhere along the way but that's all I can see. It will get MCS 3 way coilovers f&r, full spherical, etc when its time come to become a full fledged road race car but just trying to keep it simple in the fix to keep it on the street a bit longer. Im going to get it on the lift early next week and see about changing all the rubbers and see what happens. I'll start with the lca toe ones and move from there. May just start putting sphericals in everything as its getting them sooner or later.
Mine did this after I had an alignment done. Come to find out they didn't tighten the hardware for the toe adjust and it had backed off to the point it was about to fall off. Sure made for a weird ride.
My passenger-side rear lower control arm bushing split and had the same characteristics. I swapped in some Steeda bearings and it tightened up.
- 6,405
- 8,307
If the wheels were "rashed up" as you say, then I'd definately go over all the parts to see if there is something bent, the one thing I hate about IRS units is that they are very prone to getting bent, the old stick axles could be bounced off retaining walls and it would move the whole car over and keep going, that's not going to happen with an IRS.
- Thread starter
- #13
I finally got it on a lift in the shop and noticed all the other rubber bushings were swapped for for spherical except the lca toe one. swapped it out for a spherical and all seemed fine. Then I noticed some wobble in one of the rear hubs - turns out the axle nut had been off and on a couple of times (by previous owners) and had eaten the threads off so the nut wouldn't tighten. new axle and nut and driving straight again and no wobble. Ill throw it on the alignment rack when I get a chance to check it agin. Thanks everyone for all the help.
It's always the wheel hubs often the driver side one. Really really annoying.
TMO Supporting Vendors
