Beefier trailing arm bushings... as OEM!
 

Hey guys-

I've tried searching for this in past with no avail, so now that I have some pics, I thought I'd post.

I recently replaced my original '93 touring trailing arm bushings with the Mazdasport replacements (PN: F128-28-52Y). I was very happy to see that they are MUCH beefier than stock! Surprise: wheel hop goes down... with zero aftermarket parts needed. The bushings are $50 each.

I'd noticed before that the R1 and touring trailing arms carry different part numbers in the microfiche. Perhaps this is the difference... I dunno. But, I can tell you the Mazdasport ones rock. I personally don't notice any difference in ride quality, either.

The pics show the trailing arm along with the original touring bushing (the one with the tiny metal center) and the Mazdasport replacements (the one with the big metal center). Less rubber means a stiffer bushing... Oh, and the pictures are also of very poor quality. Sorry, I didn't look at the pics until after the car was back together, so it was too late to change the metering <sigh>.

Hopefully this will be useful to someone... just thought I'd share :-).

Take care,
Shad

shad,

a valuable post and the perfect fix.

the front trailing arm bushing is one of 2 key bushings that need to be upgraded... the other being the differential bushings. i run a nylon bushing but consider a higher durometer rubber bushing to be superior for a combo of aggressive street and track driving.

the reason you don't notice a significant uptick in NVH is that the trailing arm bushing does not carry the vertical cornerweight load, rather it controls braking and acceleration vectors. most fds that have not upgraded or replaced the lower link/trailing arm bushing probably should as there is alot of rubber that gets degraded.

howard coleman

Good stuff! I'll have to remember that one!

Thanks!
Dale

I recently replaced my original '93 touring trailing arm bushings with the Mazdasport replacements (PN: F128-28-52Y). I was very happy to see that they are MUCH beefier than stock! Surprise: wheel hop goes down... with zero aftermarket parts needed. The bushings are $50 each.

sounds good... where did you order from? i wonder how these compare to jimlabs?

Thanks for the replies, guys!

I ordered them from Corksport. They are also available directly through Mazdasport I believe. The pricing is about the same - somewhere around $50/ea.

I suspect that Jimlab's bushings are stiffer. These are not solid-esque bushings... there still is enough compliance to keep nice road manners. However, there's far less than stock (maybe about 1/2 or so), making it a great compromise for a sporty yet daily-driven setup. Someone with a bone stock car would not be upset at the NVH change with these, and someone who hates wheel hop would be very pleased :-).

Howard - you are correct that it's really only the longitudinal forces that go through the trialing arm. However, it's not necessarily true that all road noice comes from vertical forces. In general, passenger car tires themselves do a good job of acting like 10-20Hz low-pass filters, only transmitting 10-20Hz and lower into the suspension members. Then, the components of the suspension have to do more low-passing to keep the passengers comfortable. What keeps passengers comfortable is not a "linear" sort of thing. In fact, it's often given as a plot of threshold magnitude vs. frequency. In other words, for a given frequency, there is a certain magnitude of vibration that is "tolerable" for most people. For lateral and longitudinal suspension directions, you can often accomplish the attenuation with rubber bushings alone. For vertical, however, you need something more... most suspensions act like 1-2Hz low-pass filters...

Anyway, the point is that if you remove the longitudinal attenuation altogether, some nasty noise will come through. That said, the factory touring version had a bit too much :-).

Take care,
Shad

Mazdasport = Mazdaspeed?

Good post, thanks for the info!

F128-28-52Y

I bought these some months back and they are great. Certainly stiffer than the original stock bushings and yet no noise or harshness.

YOur not running those on a SS car are you;).

Oh hell no. I religously press the stock ones back in for every event :p:

I'd really like to get these (my home-made spherical-joint rear trailing arms are too harsh), but I don't race my FD, and the Corksport site doesn't seem to have them.

Does anyone know where they ARE available?

Thanks.

I imagine it's a case of Corksport has them, but not on their site :). Probably have to call them up.

Damon, you're crackin' me up bigtime :).

Dale

Shad and Dale, thanks for the info. I ordered them from Corksport. They have to import them from Japan, so it'll be a few weeks before I get them.

That part number also works on www.mazdamotorsports.com . We'll need two of them, correct? One for the driver's side, and one for the passenger's?

-s-

Yep - you need two. They are the same PN.

Mazdamotorsports does indeed have them, but you have to be a member, and I am not :-(. I bought them through Corksport - they were very helpful folk. Make sure you give them the PN, though... without it, they didn't know what I was talking about. It's not exactly a commonly-sold item :-).

Take care,
Shad

FYI Mazda Motorsports carries all of the stiffer Mazdaspeed rubber bushings for the FD. Just go to the catalog page and enter "F128" as all the stiffer Mazdaspeed bushings begin with that number.

Yes, I just bought a pair yesterday through the mazdaspeed website after reading this post. They arrived today.

If you need these bushings you can pay me and then I'll get them for your through Mazda Comp. I don't want to do this for a LOT of people as that's not really how I'm supposed to use the account. But I'll do it for a couple PM me if interested. It might actually end up being cheaper for you to go through corksport anyway cause if you get them through my account you'll have to pay shipping twice and CA sales tax.

Those who abuse their Mazda Motorsports membership privileges risk ruining the program for the rest of us. Don't do it!

Yeah... you're probably right. Like I said I'd maybe do it for one or two people if they're desperate to get them fast. It's not going to save them any money after tax and double shipping anyway. Nobody has taken me up on it so I think I agree with you and will recind my offer for now.

the only requirements for Mazdaspeed membership are two race results per year. Autocrosses are an easy way to get this.


Damon, do you have or know of a list of all the available Mazdaspeed parts? I tried that "F128" trick for the rear pillow ball bushings, FD01-26-220 , but it didn't work. I'm assuming there isn't a competition part available to replace these? (sorry to threadjack)

-s-

The rear pillowballs can't get any stiffer - they are already solid metal. Only the rubber-infused bushings could get stiffer.

Take care,
Shad

OK thanks for clearing that up.

-s-

Well... true Mazdaspeed does not have a stronger replacement for the stock pillowballs.

The pillowballs actually aren't sold metal... they actually rest inside a nylon housing. Not to say that they're not high performance...

You sould be able to order the mazdaspeed bushings from any dealer if you just provide them with part number. They have them in stock at the Fontana, CA mazda warehouse. You shouldn't have to wait for them to come from Japan or anything.

For those of you interested here are all the mazdaspeed bushing and mounts that are available and their part numbers:

F128-34-480 C BUSHING, FRONT UPPER CONTROL ARM (4)
Notes: 40 STIFFER THAN STOCK. FRONT UPPER CONTROL ARM, INNER BUSHING.

F128-34-471 C BUSHING, LOWER ARM SUPPORT (4)
Notes: 40 STIFFER THAN STOCK. THESE LOOK LIKE RUBBER DONUTS. THEY HELP SUPPORT THE FRONT AND REAR LOWER CONTROL ARM BUSHINGS.

F128-34-470 C BUSHING, LOWER CONTROL ARM (2)
Notes: 40 STIFFER THAN STOCK. FRONT LOWER CONTROL ARM, REAR BUSHING.

F128-34-460 C BUSHING, LOWER CONTROL ARM (2)
Notes: 40 STIFFER THAN STOCK. FRONT LOWER CONTROL ARM, FRONT BUSHING.

F128-28-460 C BUSHING, LOWER CONTROL ARM (REAR) (2)
Notes: 40 STIFFER THAN STOCK. LOWER CONTROL ARM, INNER BUSHING.

F128-28-42Y C BUSHING, TOE CONTROL (RR) (2)
Notes: 40 STIFFER THAN STOCK. INNER TOE CONTROL BUSHING ON TOE LINK.

F128-28-52Y C BUSHING, TRAILING LINK(RR) (2)
Notes: 40 STIFFER THAN STOCK. BUSHING AT LEADING END OF REAR TRAILING ARM.

F128-28-8C0 C BUSHING, UPPER CONTROL ARM (REAR) (4)
Notes: 40 STIFFER THAN STOCK. REAR UPPER CONTROL ARM, INNER BUSHINGS.

F128-28-890 C MOUNT, DIFFERENTIAL (2)
Notes: 40 STIFFER THAN STOCK.

F128-39-050A C MOUNT, LEFT ENGINE (1)
Notes: 40 STIFFER THAN STOCK. PROVIDES MORE RIGIDITY AND BETTER THROTTLE RESPONSE.

F128-39-040 C MOUNT, RIGHT ENGINE (1)
Notes: 40 STIFFER THAN STOCK. PROVIDES MORE RIGIDITY AND BETTER THROTTLE RESPONSE.

F128-28-380 C MOUNT, UPPER SHOCK (F-R) (4)
Notes: FRONT AND REAR. THIS IS MADE OF A 40 STIFFER RUBBER THAN STOCK. THIS IS NOT THE BUMPER BOUND WITH THE THREE BOLTS.

Well, it's good to see that I wasn't wasting all of my time... :D

Not according to the illustrations in the service highlights manual (just checked), and I'll be more than happy to machine one open for inspection this weekend if anyone cares strongly about it. :)

is there any advantage to replace the whole trailing arm instead of just these bushings?