My Review of Grunt Upper Bushings

[Jon K]

Well, I replaced my shimmy-maxed stock 525i bushings with 750i bushings around 145k. I am now at 176k and about 172k the shimmy started up again. The car was tramming like mad. Though the 255 rears and 235 fronts dont help that situation. But regardless, the car would shimmy retarded-like when at 60mph, and if I dared hit the brakes to get out of the 55 - 65 mph zone, my car looked like it was sneezing. So, having done new arms with 750i bushings, I decided F- it; I did just bushings this time.

I bought the grunts blue urethane upper control arm bushings. Received them moderately quickly. I took them over to Bimmers Only and the owner let me use the lift. I unbolted the arm from the car rather than seperate the ball joint and risk messing up the ball end. My mechanic made a tool that allowed for removal of bushings while on the car. It's not the same one BMW supplies. This one has variable cups so that different bushings and cars can be done. This is extremely lucky, because the OEM 750i bushings, although the same diameter, only stuck out of the metal ring by about 1/8". The grunts bushings stuck out of the metal ring by about 3/8", so if I had only the BMW cup, i'd be pressing the bushings into the arms by the blue urethane material, rather than the metal "press ring" as I like to refer to it as. Pressed the bushings in, noticing that the 750i bushings were not centered in the arms... BMA pressed those, so basically the leading side (toward front of the car) stock out of the control arm about 1/4" more than on the other side, indicated by the rust on the press ring.

Getting the arms back in was a little annoying because the arms were not as easy to pivot being that they were hooked to the rest of the suspension on the opposite end. However, I lined them back up and sent the bolt through and re-installed the washer and nut. I didn't preload the suspension. I can't imagine that there is any need to. I thought about putting the car on alignment rack to do it (thats how I did it the first time with 750i bushings) but I looked at the Grunt's configuration. There is no stationary cylinder that the bolt passes through like on OEM designed bushings. Meaning, when you torque the bushings down, it shouldn't matter where they are located (in degrees of suspension travel) because the center metal sleeve (greased) should act like a bearing and actually allow more pivot forgiveness than in an OEM bushing configuration of a stationary innard. So, with the car still on the lift, I torqued them to 3 Jon K units of tightness -- REALLY FACKIN TIGHT. I used about a 15" breaker bar and a 22mm socket to apply torque with. Things are tight.

Driver Impressions:

First, I didn't really expect to feel any difference. I am going from 750 to solid bushings, so I was pretty neutral. I noticed, however, almost immediately, that turning my steering wheel once off the lift that it seemed to be much more direct, if that makes sense. It may just be placebo also. So I took it down the road, a 35mph area. I did about 45 - 50 real quick to see. No shimmy. But then again, the 750 shimmy would go away sometimes.

Today I had my first long drive from Newtown to Lansdale for girlfriends barbeque. First thing I noticed is that the car is obviously and not surprisingly stiffer. It does transmit road feel to the steering wheel more, which I like. Howeever, since the front tires seem to be a little out of balance, it also transmits that. However the shimmy at 55 is gone. Shimmy at any speed is gone. I was thinking "Ahh urethane is going to suck bad" but it's really not. I greased the insert sleeve pretty well. No squeaks. It feels more "modified" with these bushings because I can feel more road through the wheel. When you hit transitions from concrete to asphalt its a more defined ba-thump than a messy sloppy pound to the car. Its more confident. One thing I want to say but I don't want to jinx, is that the horrible tram lining seems to be gone. I could literally ride RT-1 in NJwithout my hands on the steering wheel. The car would follow the shoulders of the groves in the highway around turns and such, very weird. This made lane changes very awkward and nervous. Now it is much more solid!

Grunt bushings so far, have a huge thumbs up from me! And if people switch from OEM solutions, I am sure they will all agree! So, once you are all done with your M5/750 bushings failing, come join the "F- 750i Bushings" club!

[Kalevera]

I torqued them to 3 Jon K units of tightness -- REALLY FACKIN TIGHT.

Hahaha!

That's great, man.

best, whit

[BigKriss]

great writeup. Only time will how they hold up. I'm trying to read your driver impressions and you talk of a more direct feel with the bushings installed. How much difference for absorbing small bumps, how much more stiffer is the car (slightly or moderalty, significantly)?

[Paul in NZ]

new 750 bushings made my car feel more direct and communicative too.Tramlining is less(235 front and rear) and car feels smoother and quieter and no more clunk.Just my non F-750 side of the story!

[Gene in NC]

If high torque is applied to the ends of the center sleeve, how can the sleeve act like a bearing or bush even if it is lubed relative to the mounting bolt?

On the other hand there is an e30 thrust bush that has a port for lubing. Assume objective is to have urethane move relative to the center sleeve.

"There is no stationary cylinder that the bolt passes through like on OEM designed bushings. Meaning, when you torque the bushings down, it shouldn't matter where they are located (in degrees of suspension travel) because the center metal sleeve (greased) should act like a bearing and actually allow more pivot forgiveness than in an OEM bushing configuration of a stationary innard. So, with the car still on the lift, I torqued them to 3 Jon K units of tightness -- REALLY FACKIN TIGHT. I used about a 15" breaker bar and a 22mm socket to apply torque with. Things are tight."

[Bill R.]

urethane bushings, if you do a search you'll find many others like it. I agree with him on this subject as well. Here's the link.

Well, I replaced my shimmy-maxed stock 525i bushings with 750i bushings around 145k. I am now at 176k and about 172k the shimmy started up again. The car was tramming like mad. Though the 255 rears and 235 fronts dont help that situation. But regardless, the car would shimmy retarded-like when at 60mph, and if I dared hit the brakes to get out of the 55 - 65 mph zone, my car looked like it was sneezing. So, having done new arms with 750i bushings, I decided F- it; I did just bushings this time.

I bought the grunts blue urethane upper control arm bushings. Received them moderately quickly. I took them over to Bimmers Only and the owner let me use the lift. I unbolted the arm from the car rather than seperate the ball joint and risk messing up the ball end. My mechanic made a tool that allowed for removal of bushings while on the car. It's not the same one BMW supplies. This one has variable cups so that different bushings and cars can be done. This is extremely lucky, because the OEM 750i bushings, although the same diameter, only stuck out of the metal ring by about 1/8". The grunts bushings stuck out of the metal ring by about 3/8", so if I had only the BMW cup, i'd be pressing the bushings into the arms by the blue urethane material, rather than the metal "press ring" as I like to refer to it as. Pressed the bushings in, noticing that the 750i bushings were not centered in the arms... BMA pressed those, so basically the leading side (toward front of the car) stock out of the control arm about 1/4" more than on the other side, indicated by the rust on the press ring.

Getting the arms back in was a little annoying because the arms were not as easy to pivot being that they were hooked to the rest of the suspension on the opposite end. However, I lined them back up and sent the bolt through and re-installed the washer and nut. I didn't preload the suspension. I can't imagine that there is any need to. I thought about putting the car on alignment rack to do it (thats how I did it the first time with 750i bushings) but I looked at the Grunt's configuration. There is no stationary cylinder that the bolt passes through like on OEM designed bushings. Meaning, when you torque the bushings down, it shouldn't matter where they are located (in degrees of suspension travel) because the center metal sleeve (greased) should act like a bearing and actually allow more pivot forgiveness than in an OEM bushing configuration of a stationary innard. So, with the car still on the lift, I torqued them to 3 Jon K units of tightness -- REALLY FACKIN TIGHT. I used about a 15" breaker bar and a 22mm socket to apply torque with. Things are tight.

Driver Impressions:

First, I didn't really expect to feel any difference. I am going from 750 to solid bushings, so I was pretty neutral. I noticed, however, almost immediately, that turning my steering wheel once off the lift that it seemed to be much more direct, if that makes sense. It may just be placebo also. So I took it down the road, a 35mph area. I did about 45 - 50 real quick to see. No shimmy. But then again, the 750 shimmy would go away sometimes.

Today I had my first long drive from Newtown to Lansdale for girlfriends barbeque. First thing I noticed is that the car is obviously and not surprisingly stiffer. It does transmit road feel to the steering wheel more, which I like. Howeever, since the front tires seem to be a little out of balance, it also transmits that. However the shimmy at 55 is gone. Shimmy at any speed is gone. I was thinking "Ahh urethane is going to suck bad" but it's really not. I greased the insert sleeve pretty well. No squeaks. It feels more "modified" with these bushings because I can feel more road through the wheel. When you hit transitions from concrete to asphalt its a more defined ba-thump than a messy sloppy pound to the car. Its more confident. One thing I want to say but I don't want to jinx, is that the horrible tram lining seems to be gone. I could literally ride RT-1 in NJwithout my hands on the steering wheel. The car would follow the shoulders of the groves in the highway around turns and such, very weird. This made lane changes very awkward and nervous. Now it is much more solid!

Grunt bushings so far, have a huge thumbs up from me! And if people switch from OEM solutions, I am sure they will all agree! So, once you are all done with your M5/750 bushings failing, come join the "F- 750i Bushings" club!

[bahnstormer]

when i get back to the states ill take a quick drive jon to see what they feel like =] hopefully ull be blown by then =]

[Jon K]

when i get back to the states ill take a quick drive jon to see what they feel like =] hopefully ull be blown by then =]

Its funny, I was trying to get in contact with you because i had to end up ordering my supercharger pulley from Germany... I was going to see if I could ship it to you in Poland or wherever, but no luck. $347... fack.

[Anthony (M5 in Calgary)]

So, once you are all done with your M5/750 bushings failing, come join the "F- 750i Bushings" club!

Ummm, I put new M5 bushings in my M5 at 121,000kms. The original parts (as evidenced by the date code) were just fine - no cracks or softness.

Reason for replacement? TA ball joint failed on one side, bought arms (Lemfoerder) from BMA with new bushings to avoid extra work in the garage.

Would Brett make a similar comment about applying 750 or M5 bushings on 525s or 535s as he does for urethane?

[Kalevera]

Ummm, I put new M5 bushings in my M5 at 121,000kms. The original parts (as evidenced by the date code) were just fine - no cracks or softness.

Reason for replacement? TA ball joint failed on one side, bought arms (Lemfoerder) from BMA with new bushings to avoid extra work in the garage.

Would Brett make a similar comment about applying 750 or M5 bushings on 525s or 535s as he does for urethane?

We'd use whatever's stock for the car unless the customer wants something else. An E34 525/530/535/540 thrust arm bushing job hasn't come in yet in my time at KMS, but I suspect it would get whatever the dealer would stick on the car. The subject of the video on faulty urethane bushings, an M5T, received M5 bushings and stock arms.

Why? For the same reason we use BMW Synthetic Oil (versus anything else): warranties.

best, whit