Lower control arm hitting rotor backing plate

[Kevin]

Hey all! I've run into a problem I was wondering if any of you all have experienced. I replaced my brake discs a while back and since then, I've heard a scraping noise on sharp turns on my left front wheel (assuming that's the only wheel, hard to tell if the right wheel does it). So I decided to investigate tonight and found the bottom of my LCA is hitting the brake disc backing plate on sharp turns and is scraping my new brake disc.

I'm guessing I've just got the luck of the draw with my specific suspension setup (Grady springs, beefy Heninger arms, new thick DMC rotors) and maybe even alignment and ball joints are in play, but was wondering if anyone else experienced this and knew exactly which way to shimmy things to fix it.

[David T]

What you have there is very bad. The rotor disc looks like it may be beyond saving. It may be possible to grind the end of the lower control arm to get more clearance. When you start mixing and matching non-standard parts no one has experimented with all of the possible combinations so it is impossible to know what is going to work with what. It is strange it is only happening on one side. I would see why the other side is OK and see what you can do to make the bad side work like the good side? You cannot just shim for clearance, you will affect the alignment which should have been set up when you replaced all of these parts.
David Teitelbaum

[Kevin]

Thank you, David. Yes I think I'll take a look at the other side and see if I can figure out what's different.

[Spittybug]

When I boxed and reinforced my LCAs with a thin strip of sheet metal wrapped around the "nose", it would sometimes bang up against the dust shield. I had to grind it down a bit. I'm not familiar with Heninger's beefier LCAs, but if they have added any material to the ball joint end, that may be what is happening to you.

[Kevin]

Thanks for sharing your experiences, Owen. Yes it's sounding more like I may just have to grind back that bit.

[FABombjoy]

When did you purchase Byrne's LCAs? A set that I purchased from 2 years back had the same problem due to balljoint misplacement. I removed the shields and altered the LCAs with a grinder as a temporary fix but for me the excessive positive camber was the bigger problem.

I'd contact him ASAP and let him know what is going on. You should do a quick camber check on both sides and test if it's positive. Even if only one side is grinding they both may be out of alignment spec and need to be replaced.

[Delorean Industries]

When did you purchase Byrne's LCAs? A set that I purchased from 2 years back had the same problem due to balljoint misplacement. I removed the shields and altered the LCAs with a grinder as a temporary fix but for me the excessive positive camber was the bigger problem.

I'd contact him ASAP and let him know what is going on. You should do a quick camber check on both sides and test if it's positive. Even if only one side is grinding they both may be out of alignment spec and need to be replaced.

The distance between the center line of the ball joint and center line of the rear bushing sets the vehicle camber. If this is off any it will have this issue.

[Kevin]

When did you purchase Byrne's LCAs? A set that I purchased from 2 years back had the same problem due to balljoint misplacement. I removed the shields and altered the LCAs with a grinder as a temporary fix but for me the excessive positive camber was the bigger problem.

I'd contact him ASAP and let him know what is going on. You should do a quick camber check on both sides and test if it's positive. Even if only one side is grinding they both may be out of alignment spec and need to be replaced.

Thank you, very interesting to hear you having the same problem. I discounted that it may be my camber at first, but I just checked my alignment sheet from when I got an alignment a few months ago, and it turns out, it is slightly positive (0.4 degrees), which I've just discovered is out of spec. Service bulletin ST-34-1/82 (http://www.dmcnews.com/bulletins/ST-34-1.82.html) says it should be -0.5-0 degrees, so NOT positive at all. My alignment shop's specs said -2.5-2.0 degrees which is why it was in spec before.

I'm always bringing in the specs from now on, I had to go back and get them to fix my rear camber because their computer had too wide of a spec and I was getting uneven tire wear from it, and now my control arm is ruining my rotor.

Thanks again, FABombjoy, this is probably my best bet and I'll likely try this first, I don't want to go modifying parts just yet.