lcbusa1300 Posted August 1, 2014 Share Posted August 1, 2014 I've recently developed horrible shake in the rear of my 280z when I'm off the gas. As long as I'm on the gas it's smooth, but when I take my foot off the gas it instantly starts to shake. This only occurs above 50 mph though. I jacked it up and looked today and noticed both my mustache bar bushings are literally gone. I don't know how I've over looked this before but I did. I'm obviously going to replace them anyways, but it'll be a few weeks before I get to it. So I'm curious ahead of time to see if anyone thinks this is the culprit or something else? BTW, I've checked the half shafts and they seem solid along with the ujoints. The differential mounts also seem solid. I also replaced the springs and struts 6 months ago so I know it's not that. Quote Link to comment Share on other sites More sharing options...
z240 Posted August 1, 2014 Share Posted August 1, 2014 (edited) You need to get those bushings replaced ASAP. There absense is the cause of your shake rock and roll. That diff has huge forces on it that need to be properly constrained. Just imagine why they made the mustache bar so long and you can imagine the torque it has to hold. Edited August 1, 2014 by z240 Quote Link to comment Share on other sites More sharing options...
lcbusa1300 Posted August 1, 2014 Author Share Posted August 1, 2014 Thanks man, I figured as much. I racked my brain trying to figure out where that was coming from and somehow managed to overlook the largest, most visible bushings in the rear. I've got them on the way should have em swapped out next week. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted August 2, 2014 Share Posted August 2, 2014 (edited) Anxious to see how this goes, those bushings are high, away from the weather. Never seen any that weren't perfect once the mustache bar was down. I've burned several sets out for poly, and thought "wow, I just destroyed a perfect bushing." I'm still betting on a u-joint, or tire out of round or out of balance, or worst case: rear hub bearing. Be sure to check all your lug nuts for torque. Edited August 2, 2014 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
lcbusa1300 Posted August 3, 2014 Author Share Posted August 3, 2014 Rebekah, I guess I'm not understanding your comment. The bushings are definitely shot. I can see shiny metal where the mustache bar has been clunking up and down. However, I can't guarantee this is the source of shaking. If it was a bearing, u joint, or unbalanced tire wouldn't it be consistent rather than only when I'm coasting? It's as smooth as butter as long as I'm applying throttle, but as soon as I let out it goes to rattling in the back. I'm no mechanic, but I assumed when I was in the gas the torque was holding the differential/mustache bar stationary, and when I'm coasting it's able to move about. Quote Link to comment Share on other sites More sharing options...
lcbusa1300 Posted August 3, 2014 Author Share Posted August 3, 2014 Wow, just realized those are studs coming off the back of the differential. I'm guessing the differential has to drop to get the bar out. Dang. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted August 3, 2014 Share Posted August 3, 2014 You could pull the studs out if you were so inclined. Granted removing everything will give you a chance to clean some things up and inspect the u-joints that could be in question. rebekahz's line of reasoning isn't bad. If you are not under load, then the diff should be hanging on the washers, and the ride should still be somewhat smooth, a worn u-joint would make diff vibrate a bit which would only be amplified with worn bushings. I vote you pull it off, take off the axles and drive shaft while you are at it and inspect all 3 while you replace the bushing (both front and rear), unless the half shaft/driveshaft/front bushing has been recently serviced, then I would try to extract the studs to save the extra work. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted August 3, 2014 Share Posted August 3, 2014 Wanna post us a cell phone pic,(?) I'm not even sure we are talking about the same bushings...maybe we can save you some work, and money and time. If you see lotsa slop in a fastener, it's probably the problem-we may just be getting out terminology mixed up. Quote Link to comment Share on other sites More sharing options...
lcbusa1300 Posted August 4, 2014 Author Share Posted August 4, 2014 Yeah I see what ya'll are saying. I guess I'm hanging on the hope it's the bushings and refusing to believe it may be something worse. I'll get some pictures in the morning and post them, and maybe we can clear a few things up. Quote Link to comment Share on other sites More sharing options...
lcbusa1300 Posted August 12, 2014 Author Share Posted August 12, 2014 Well, it was the mustache bar bushings. Replaced them a couple days ago and it eliminated the shaking and clunk when I take off. While I was under there I replaced the control arm bushings with MSA's camber adjustment bushings which I'm not happy with at all. They allowed me to fix the toe issue I posted about a few months back. However, I wouldn't recommend them to anyone who daily's their car. They are so noisy it almost makes me think I did something wrong. I've crawled under there twice and checked bolts and everything seems to be okay. I'm thinking about starting a new thread on this since I can't find any info about people running them. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted August 13, 2014 Share Posted August 13, 2014 I'm so glad I was wrong! Honestly, I don't mind being wrong one bit-I'm just so glad you are back on the road. I was wondering how it was going and have thought several times to ask for an update. I used to run the camber bushings in order to reduce the negative camber induced from lowering the car. I hatde all the noise too! Try running them down a gravel road! Bridge seams in the asphalt are total joy-if you like going to the dentist and getting your fillings knocked out! I pitched them and got bolt-in camber plates (which cause a little noise too, but not nearly as bad). But, I already had coilovers, so it wasn't that big of a deal to add the camber plates and adjust camber from the top. if you want to control toe, I think your best option that is readily available is the TTT adjustable LCA. Do you have any pics of the trashed M-bar bushings? I'm trying to remember how that bushing is made: there is a sleeve encased in rubber that is vulcanized to the inside of the mustache bar loops...are there bushings that I've forgotten about that sandwich the mustache bar between the big washer and the "frame?" When I was thinking that I'd never seen a bad bushing, I was thinking of the vulcanized part that you have to burn out with a torch to install aftermarket poly bushings. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted August 13, 2014 Share Posted August 13, 2014 A light wrap of teflon cleared up the noisy bushing on my daily. On the datsun I lubed everything really well, and haven't had problems yet. I do mean I lubed everything though. Inside of the bushing, the outside of the bushing, the inside of the sleeve, the outside of the sleeve and the mounting location. My chassis creaks now but the bushings are pretty silent. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 13, 2014 Share Posted August 13, 2014 They are so noisy it almost makes me think I did something wrong What kind of noise are you hearing? Squeaking, banging, clunking? Are you sure that those are the cause? You did several things in one operation. Quote Link to comment Share on other sites More sharing options...
lcbusa1300 Posted August 13, 2014 Author Share Posted August 13, 2014 (edited) @RebekahsZ Ha in this case I'm glad you were wrong too. Once I got it apart I realized what you were talking about. The bushings were dry and sloppy but didn't look nearly as bad as I thought they were. What I had been looking at was the "Teethed" looking rubber between the big washers that I thought was suppose to be part of the bushings themselves. Yeah you're spot on about how they're made though. I drilled a hole in them then using that hole I took a saber saw and cut my way around. Then I scraped the remaining rubber out. Ill have to check into more toe options, those camber bushings were just the cheapest option. I guess you do indeed get what you pay for. @seattlejester I didn't think about teflon, unfortunately. I knew the control arm bushings being metal on metal was going to be noisy though, so I caked them in grease hoping that was help some, but I can't imagine it made much of a difference. @NewZed It's like a roaring sound. It'll roar a few miles then it'll get silent a few miles. It almost sounds like a hub bearing, but I have a hard time believing I've developed a bad wheel bearing since installing the bushings Sunday. Yes I installed the mustache bar bushings first and took it for a ride to see if they were indeed the culprit of my original problem, and they were. I drove it to town and back, and it was perfectly smooth other than the little bit of noise I expected from polyurethane mustache bar bushings. I brought it home and installed the control arm bushings. When I was done I took it for a ride, and the noise was immediate. That was my thinking though. I thought well since I did several things at once maybe I forgot something under there, but I've crawled back under there twice looking for something and can't find anything. Edited August 13, 2014 by lcbusa1300 Quote Link to comment Share on other sites More sharing options...
lcbusa1300 Posted August 13, 2014 Author Share Posted August 13, 2014 (edited) BTW, this is what it took to get one of the control arm bushings off. I ended up having to take the whole control arm/hub assembly/strut out together. I heated it with a torch, torqued on it with a 24inch pipe wrench before having to ultimately shave it off with a chisel. Never seen anything like that in my life. The other three slid right off by hand. Edited August 13, 2014 by lcbusa1300 Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 13, 2014 Share Posted August 13, 2014 You mean the bolt, not the bushing...? On the noise, you've created a more solid path, aside from the tiny sliver of rubber at the small end of the arm, from the tires to the body, with the toe/camber adjuster. Delrin is pretty hard material. The on-off nature is probably just pavement quality. Bummer. On the other hand, if you were racing, it might be a fair indicator of available traction. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted August 14, 2014 Share Posted August 14, 2014 My aluminum camber bushings were silent on a smooth roadway. But run over a plastic reflector when changing lanes and "bam!" It sounded like hitting metal on metal like putting a rock in a tin can and giving it a slap. On a gravel road it sounded like someone was shaking that tin can with a rock in it giving it a "crunch, crunch, crunch sound. It wasn't a roar. Quote Link to comment Share on other sites More sharing options...
lcbusa1300 Posted August 16, 2014 Author Share Posted August 16, 2014 You mean the bolt, not the bushing...? On the noise, you've created a more solid path, aside from the tiny sliver of rubber at the small end of the arm, from the tires to the body, with the toe/camber adjuster. Delrin is pretty hard material. The on-off nature is probably just pavement quality. Bummer. On the other hand, if you were racing, it might be a fair indicator of available traction. Not sure what you mean in the first question. If you're referring to the picture, then no I meant that bushing. I know it sounds ridiculous considering those just slide on and off but it was completely seized. As you can see in the picture I eventually got mad and just shaved it off. Anyhow, yeah I know I created a much more solid path from my butt to the road with those bushings. I can now feel every crack in the road and even changes in road quality. I expected all of the noise except for the one i'm trying to describe. My aluminum camber bushings were silent on a smooth roadway. But run over a plastic reflector when changing lanes and "bam!" It sounded like hitting metal on metal like putting a rock in a tin can and giving it a slap. On a gravel road it sounded like someone was shaking that tin can with a rock in it giving it a "crunch, crunch, crunch sound. It wasn't a roar. Yeah, I expected those noises, but not the one I'm failing to describe. It's not a steady, consistent roar but more like a unbalanced tire without the shaking. It comes and goes in a fairly timely manner. For instance, It'll "roar" for 5 miles, then get smooth for 5 miles and back and forth. I can't correlate it to any road quality or anything else. I can't find anything , so I'm reluctantly going to rule it off as metal on metal bushing noise and try not to mind it. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted August 16, 2014 Share Posted August 16, 2014 Every diff I ever had was pretty noisy-that's kind of a roar. Quote Link to comment Share on other sites More sharing options...
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