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As the title states I'm having grinding on the rear passenger side while turning left only. No grinding under hard acceleration (that I can hear/feel) anyone else have that issue? I autocross this car and I'm a little worried about potentially damaging the axle or coilover. Have not gotten it aligned yet, this is all thats holding me back.
Thanks for any help
Last edited by L98Justin; Apr 17, 2020 at 03:38 PM.
On the later cars, youbhave to modify the top plate to tilt the shock forward a half inch and that gives you clearance. Not sure how you do that in the 84-87 cars as it has a fixed mount, without some cutting and welding.
Alignment (too much negative camber) can cause interference. Where are rub marks?
I'll take a picture when I can, I initially heard it and checked and you can see the line where it "polished" the aluminum. I do have a bit more negative camber and my toe I'm certain is off as well
This is the driver side, it did this on my way to the alignment place a week or so ago, I turned the spring and it gave me better clearance, the passenger side initially didn’t scrape, but after my most recent test drives will scrape enough to hear it while turning
I'm removing the cheap adjustable camber bar you see here, the adjustable bar is almost impossible to turn on the driver side, the passenger moves freely. I've ordered the EM heim jointed camber arms to replace these.
Last edited by L98Justin; Apr 19, 2020 at 08:12 AM.
Not exactly what I was expecting. I would mount the spare and roll on ramps. Then see how it all fits together. Is upper shock mount bracket adjustable?
Not exactly what I was expecting. I would mount the spare and roll on ramps. Then see how it all fits together. Is upper shock mount bracket adjustable?
not really adjustable, it uses washers and offset retainers to push the coiler as far forward as they can go within the stock bracket. I've jacked up the rear and spun the tires there is no contact at that point it's only when I turn a littler quicker than normal which will certainly happen when I autox it.
Last edited by L98Justin; Apr 19, 2020 at 08:14 AM.
You really need to see where everything is with weight on suspension. I went with spare is overall smaller and would allow more to look around. I would contact EM before trying to modify supplied parts. How much clearence is on the opposite side
You really need to see where everything is with weight on suspension. I went with spare is overall smaller and would allow more to look around. I would contact EM before trying to modify supplied parts. How much clearence is on the opposite side
unfortunately I don't have a spare, I did crawl underneath the car and I cannot put a pinky finger in between the driveline and the coilovers
Last edited by L98Justin; Apr 19, 2020 at 08:15 AM.
On the left rear you need a bracket like this so you can slide the bottom of the shock forward just enough to clear the axle.
you need at least 10 mm of clearance at static position between spring and axle.
On the left rear you need a bracket like this so you can slide the bottom of the shock forward just enough to clear the axle.
you need at least 10 mm of clearance at static position between spring and axle.
Merle certainly didn't tell me that. I called and did my homework the best I could and I never found or was told anything about the bottom bracket needing to be pushed forward on the rear knuckle shock bolt. I'll try my stock bolts and see if I have any luck since I certainly don't have the tools nor the skill to fabricate something like that.
This is the problem with rear coilovers on C4s, in general. The Ridetech kit is the one that really effectively addresses this problem. That Speedway part is likely going to result your breaking the mounting lug off the knuckle at some point. Addendum: the bracket that blackozvette is describing could help, but don't just add it to one side you'll have different damping geometry on each side. Add it to both sides. I'm assuming that's what he meant, so I'm just clarifying.
Also, I don't understand how alignment (camber or toe) can significantly affect this one way or the other. And if you can't run much negative camber - which is desirable for autocross or road course runs - then the coilover kit seems self-defeating. I would, however, double-check to make sure your halfshaft U-joints are in good shape. If one of the joints on that side is bad, it could allow the halfshaft to move off its intended axis just enough to make contact. That's unlikely, but it's worth a check before moving forward.
It looks to me like you're running these coilovers at a lower ride height than EM ever tested, which is resulting in the lower perch or spring interfering with the halfshaft. It's possible you're running the car so low that it's not going to be good for handling (hitting bump stops). However, you shouldn't need to add homemade brackets or extensions to a kit that's supposed to fit your car. Honestly at this point, instead of doubling down on EM parts (the camber rod), I'd send the coilovers back and plan a different solution.
Last edited by MatthewMiller; Apr 19, 2020 at 11:51 AM.
This is the problem with rear coilovers on C4s, in general. The Ridetech kit is the one that really effectively addresses this problem. That Speedway part is likely going to result your breaking the mounting lug off the knuckle at some point. Addendum: the bracket that blackozvette is describing could help, but don't just add it to one side you'll have different damping geometry on each side. Add it to both sides. I'm assuming that's what he meant, so I'm just clarifying.
Also, I don't understand how alignment (camber or toe) can significantly affect this one way or the other. And if you can't run much negative camber - which is desirable for autocross or road course runs - then the coilover kit seems self-defeating. I would, however, double-check to make sure your halfshaft U-joints are in good shape. If one of the joints on that side is bad, it could allow the halfshaft to move off its intended axis just enough to make contact. That's unlikely, but it's worth a check before moving forward.
It looks to me like you're running these coilovers at a lower ride height than EM ever tested, which is resulting in the lower perch or spring interfering with the halfshaft. It's possible you're running the car so low that it's not going to be good for handling (hitting bump stops). However, you shouldn't need to add homemade brackets or extensions to a kit that's supposed to fit your car. Honestly at this point, instead of doubling down on EM parts (the camber rod), I'd send the coilovers back and plan a different solution.
I'll remove the speedway part, I used it based on a thread here on the forum of another member using it with his coilovers, Halfshafts and U joints seem strong as well as the wheel bearings. you're probably right on them being too low. I'll adjust them tonight and get back to you. I'm determined to make this work, so however foolish it is to not send them back I'm gonna keep working on it, the EM camber rod needs to happen anyways since I currently have the poly adjustable that many other Autox guys on this forum advise against.
Thanks @MatthewMiller much appreciated for the insight, I'm the only C4 running in my local group so asking some of my local veterans for help hasn't proved useful so far.
I'll try @blackozvet solution if I can find someone to build it for me and nothing else has helped my issue
Last edited by L98Justin; Apr 19, 2020 at 12:49 PM.
To be clear, I'm all in favor of getting poly bushings out of the rear suspension links.
I wonder if you could use a shorter spring and raise that perch substantially for the same ride height? Would that get the perch out of the haflshaft's way? Just a thought that crossed my mind.
To be clear, I'm all in favor of getting poly bushings out of the rear suspension links.
I wonder if you could use a shorter spring and raise that perch substantially for the same ride height? Would that get the perch out of the haflshaft's way? Just a thought that crossed my mind.
the halfshaft isn't hitting the perch its contacting the coil itself, the coating on the coil is rubbing off already on the area it was hitting. The distance between the coil and the halfshaft is more or less my pinky finger under full load
EM Coilover grinding on axle
