fireroasted

iTrader: (3)

I decided to install the Whiteline rear diff bushings and mustache bar bushings. I have been experiencing some violent clunking at times on track, and some part throttle bucking in parking lots. From what I have read these two bushings should help resolve some of that behavior for compromising some noise and vibration insulation.

The rear diff bushings are a very easy install. On a scale of 1 to 10, 10 being an engine build and 1 changing your tires, this is likely barely a 3. The big question is weather you will press out the bushings yourself, or get a shop to do it for you.

From the ground the finished environment looks like this:


Obviously the yellow bushings are the new whiteline ones. I don't have big washers on the end like some posts suggest to provide, but I left it like this as this is how they came. I will likely be reusing the stock washers, but this made for a better pic.

Place a jack under the diff just barely touching. then undo the 19mm large bolt that goes through the bushing; the vertical bolt. The diff may tilt forward slightly to rest on the jack. Its still attached to the mustache bar in the rear too.

Then remove the 3 17mm bolts from the side, which hold on the bracket. These brackets you will remove so you can get the bushings pressed out. Once removed it should look something like this.


You can press the bushings out with a Harbor Freight bottle jack press, which I have done, but this time I got lazy and took everything to my neighborhood machine shop that pressed everything for 30 bucks. You can't beat that. Their press is a zillion times better than mine and I don't have to curse. However its possible at home. Some guys do it without a press, but I don't think its worth it. (For you SoCal guys, Freeway Auto on Avery exit and the 5 rocks it for this kind of stuff).

The WL bushings is 3 pieces. 2 urethane pieces/halves that push into the bracket, and then a shaft that presses into them, I don't have a pic of this, but you can assemble this in a vice, or even tap the shaft in with a hammer. Its snug but doesn't require a press. You can use the WL provided grease to make it much easier.

The smaller or shorter of the halves goes on top. Then mount the bracket back onto the diff finger tight. Then you can locate the diff just right and fit the long 19mm bolt through the new bushing and fasten. If you are only doing this bushing, get everything snug, evenly then tighten. Done.

If you are also doing the mustache bar bushings.........

fireroasted

iTrader: (3)

you should consider dropping the subframe entirely, based on my experience. I first tried just lowering the subframe, which has 8 bolts holding it to the body, and that was OK for just removing the mustache bar, and even OK, for getting it back in there, but then I couldn't get the new mustache bar bushings inside of the subframe. This forced me to completely remove the subframe so I could beat on the mustache with a mallet. So if I was doing this again, I would just start with removing the sway bar, then removing the lower link (camber bolt adjustment).

Here is a shot of the subframe and mustache bar out of the car and joined back together. This is the end really, but this gives you a good idea where the bolts are that hold the subframe to the body.


Some arrows to help see where the connections are before you start at it. If you go and drop the subframe entirely then you will want a small jack under the center two bolts. Take those out first entirely, and place the jack there. The unit is fairly balanced form this center.


Then make sure you disconnect the rear of the diff from the mustache bar itself with the 3 17mm bolts. You will need a wrench, and preferably one with a ratchet, because a socket won't fit in that space, and it will take lots of flipping around with a tranditional wrench before you get all the threads undone.

Now the subframe will lower with the mustache bar attached. The mustache bar will separate easily with the old bushing. The 17mm bolt and nut will come out easily, and then just push the mustache bar out.

Now if you left the sway bar on and lower link attached, and just lowered the subframe it will hang in place and isnt' as heavy as you might think. You can loosen the mustache while in there, and then wiggle the unit to the side, towards one of the wheels. You will need to lift the mustache out of the 'holder' of the subframe to one side, and now you can twist the mustache out the back of the car, but over the subframe. So it will come out between the subframe and the bottom of the car (spare tire compartment).

Here is the subframe lowered from the body. The gap above it is plenty big to twist out the mustache bar. And you can get it back in that way pretty easily.


What I couldn't do is get the mustache bar with the new bushings to slide back INTO the subframe openings. With it in place like this I also didn't have any leverage to do anything. I tried a bunch of banging and prying and jacking, but nothing was working. I had to give up and remove the subframe entirely. You can see here its in place, but I couldn't push the bushings into the openings.


After some beating on the mustached I was able to line up the holes so the bolts could go through easily. I fastened the mustache to the subframe, and then installed the subframe with mustache attached.


This is how I got the photo of the unit above. Here you can see the view of the gap between the subframe and the body looking at the mustache just before I attached it back to the rear of the differential.


It may depend on your bushings, but if they are the whiteline ones you see in my pic then they are super tight fit even totally lubed up, and you need to beat them in there, and for that you need the subframe out of the car. Other bushings may be easier to fit, and you can do this by just losening the 8 bolts of the subframe to create that 'gap' to twist the mustache in and out.

I also had these bushings pressed out and the new ones pressed in. Again you can do this at home with a HF bottle jack press, but if you find a cheap solution I suggest getting a big press where they have zillions of sleeve sizes to match up perfectly and pass on that DIY part.

Here is a good shot of the units you are trying to remove and reinstall.

fireroasted

iTrader: (3)

Driving Impressions:

I experienced some severe clunking at my last Laguna Seca track day. It was actually new, so I figured it was something else, like brakes or suspension, but nothing was traceable in the pit. later in the day the issue subsided. I started researching the 'clunk'.

I also had some sever clunking while getting a troubleshooting set of dyno pulls at Road Race Engineering a couple of years ago. It was odd, and I could never find out what it was. I suspect it was the same thing now.

And finally I also would experience annoying and embarrassing bucking in parking lots under part throttle 1st or even 2nd gear. I would have to manage that by feathering the clutch for everything. If I didn't slip the clutch the car would buck ever increasingly without any throttle changes. Essentially it was yoyo ing up almost lunging the car around.

My goal was to address all of these with both bushing sets. In my first test drive I believe I have addressed all of it somewhat, but not entirely. The parking lot bucking is the only thing I could really test, and this is definitely different and feels significantly reduced. I will have to daily drive for a week, and then report back. I will also need to see if any track time bucking happens at my next track day. As for dyno test, I don't have any plans to be on one so I can see/hear that again like I did at RR. I will provide more valuable feedback as it develops.

rrstlevo

iTrader: (14)

In for results!!! Damn parking lot bucking!!!

Thoe99

iTrader: (25)

The front motor mount made the most difference in my lineup of mods I did to try to improve drivetrain slack. After that, nothing else made significant difference. In fact, after doing the 3 motor mounts (minus the rear), the mustache bar/rear diff bushings were almost completely useless. All it did was increase any vibration I previously had.

rh9

would these bushings work on evo7 with ayc rear diff ?

WRC-LVR

iTrader: (1)

very nice writeup and pics.

I might offer that a couple of large C clamps would have pulled those mustache bar bushings into place. Lining them up is easier if you use a pointed bar in the bushing and wiggle it to line them up. lubing the outside of the bushing faces will also allow the bushing to slide down into the carrier easier as well.

Nimpoc

iTrader: (17)

Nice write-up. I was thinking that the subframe was going to have to come out anyway as it's a nice package with the diff to allow restacking.

I had REALLY bad slack too. A BLOX front mount took care of most of it, and amazingly did really improve shifting, and make the dash buzz. That was done first. Both side mounts were cracked so those were replaced with new factory parts. At the same time I had the TC serviced by Jacks, who reshims everything... Now it's all about OEM tight with just a touch of lash left. I can see the mustache bushings are cracked pretty bad, so I ordered new OEM parts for only like $16/each. I'm hoping that'll take care of it.

akqowns

iTrader: (6)

Diff / mustache bushings + blox front engine mount will make whining noise ( pretty much same as death whine but quieter and constant unlikely death whine ) only occurs at 60-70 mph tho. it's known issue.

fireroasted

iTrader: (3)

Did the blox front mount reduce or eliminate your bucking/lash? I am considering it, but even more dash buzzing could be the end of me. I have an OCD with buzzing and noise stuff. I can't see for crap, but I hear everything. I already have a pretty noise cabin, because its a built trans with a stage 2 TC, and now all the stiff bushings in the rear.

I do want to get rid of the parking lot bucking. I can definitely impact it by reducing the MIVEC advance, but that is the trade off, but that advance gives me slightly better spool characteristic. But, if I am not getting on it, like in a parking lot, my driving looks like jackhole superstar crap box.

akqowns

iTrader: (6)

Blox engine mount will reduce bucking theoretically , but it's not like night and day different. In my opinion, these differential/ mustache bar bushings helped more than engine mount, but this also not night and day different. They aren't hard to install nor expensive, so give it a try if it satisfy you. I'm really picky about noise and stuff, so these didn't really do much for me.

Nimpoc

iTrader: (17)

In my case, the BLOX mount did help a lot. However, the stock front mount was in bad shape and cracked, as well as the side / rear mounts, as well as probably every other piece of rubber in the car that I've not yet replaced. The very stiff BLOX mount was likely (over)compensating for all kinds of other slop in the car.

From here on out I'll just be trying to put in new OEM rubber bushings under the assumption that they are all simply wearing out. The car was initially delivered without any drivetrain lash, fantastic performance, and acceptable NVH. The bushings need to be considered wear items like tires and belts.

golgo13

iTrader: (134)

I'm about to do this, great write up, fireroasted!