IRS Bushing Questions

[03Cobra745]

I've been reading about how replacing the IRS Bushings reduces wheel hop and improves handling. So, I called Steeda to order the bushings and when they arrived, I had only received two bushings, for the IRS Differential Mounts. I then looked at the Steeda Catalog and noticed there are also IRS Control Arm Bushings and Rear Subframe Bushings. Which ones should I have ordered/installed?

Also, I've read that changing out the 12mm IRS Bolts for 14mm Bolts helps. I asked Steeda if they carry the 14mm Bolts and they do not. Which IRS Bolts are these? If I tell my Ford Mechanic to change these bolts, will he know what I'm talking about and will the dealer have them in stock?

Cheers!

 

[jordanvraptor]

It is the Maximum Motorsports IRS bushings that you are thinking of. http://www.maximummotorsports.com/mmirsu.asp

The Ford dealer may change out the 14 mm bolts in the front IRS mounting position but more than likely they wont since Ford specs a 12 mm bolt for this location. These bushings and the differential bushings will help with wheel hop but won't completely eliminate it.

 

[03Cobra745]

jordanvraptor,

Thanks for the advise. Just got off the phone with Maximum Motorsports and ordered the Subframe Bushings & 14mm Bolts.

Seeing that I'm going to replace the Differential & Subframe Bushings, I said "What the heck." and ordered the IRS Control Arm Bushings.

Cheers!

 

[PACETTR]

Let me know how these work, as I plan on installing them on my 89 as time permits.:thumbsup:

 

[BlueOvalBill]

Originally posted by bhartman
jordanvraptor,

Thanks for the advise. Just got off the phone with Maximum Motorsports and ordered the Subframe Bushings & 14mm Bolts.

Seeing that I'm going to replace the Differential & Subframe Bushings, I said "What the heck." and ordered the IRS Control Arm Bushings.

Cheers!

I'm no expert, but I've read that polyurethane is not a good material to use for joints that rotate, which is what the LCA and UCA joints do. For these joints, delrin is a better material than polyurethane. You can get delrin UCA and LCA bushings from [email protected]. He also sells aluminum pinion bushings and a delrin bushing for the differential cover.

Good luck with your rear suspension mods.:beer:

 

[toofast4u]

Urethane is fine for some applications mainly static locations that don't see high temperatures. They suffer from cold flow, deformation, squeak, and are affected by high temperatures. The UCA and LCA locations are pivot points which is not a good application for urethane IMO specifically due to problems with cold flow and squeaking. They are more likely to hinder suspension movement though due to there stickyness which often is the cause of them being squeaky.

I am a major supporter of Maximum Motorsports and they actually know me by name which is scary, but I would recommend against using there urethane CA bushings. I believe they are going to be releasing a Delrin version of the CA bushings soon which is a much better solution.

As far as the differential bushings go I had the Steeda urethane pinion bushings on my car. After about 3 months they were deformed and started melting from the heat. The most significant problem with this is that the differential is only supported by two mounting locations the pinion and cover. When the pinion is no longer supporting the differential where do you thing the entire load is going. I now have aluminum pinion bushings on my car and they are much better. I have the Kenny Brown on my car now, but would recommend them or buy them again. The problem is they were not designed correctly for our IRS. They are too small to correctly fit this location and if you install them per the instructions it will change your pinion angle and is not able to keep the pinion from moving. I had to add 3 large washers actually the three washers from my old Steeda bushing between the pinion and the IRS assembly to make the bushings fit correctly. There is a guy now making aluminum pinion bushings for our IRS that fit correctly [email protected] he is who made my Delrin CA bushings and Delrin differential cover bushing.

 

[03Cobra745]

I wanted to go with the Kenny Brown aluminum bushings, but read various posts concerning installation problems. I would think :??: the Polyurethane bushing would work fine, because this is what most shops (Steeda, MM, etc.) are selling as replacements for the stock rubber bushings.

Oh well, I'll get them a try... :shrug:

toofast4u,

You said the Steeda differential bushings only lasted 3 months. How many miles and what kind of driving?

I put little mileage on the Cobra, but do participate in on-track events.

 

[toofast4u]

Originally posted by bhartman
I wanted to go with the Kenny Brown aluminum bushings, but read various posts concerning installation problems. I would think :??: the Polyurethane bushing would work fine, because this is what most shops (Steeda, MM, etc.) are selling as replacements for the stock rubber bushings.

Oh well, I'll get them a try... :shrug:

toofast4u,

You said the Steeda differential bushings only lasted 3 months. How many miles and what kind of driving?

I put little mileage on the Cobra, but do participate in on-track events.

A lot of places sell urethane because it is cheap and easy to sell. Trust me the more you use urethane the more you will grow to hate it. My Delrin CA bushings were $300 at that is a very good price for them. Kenny Brown in general sucks I knew it when I bought the aluminum bushings, but they were the only people making them at the time. The KB aluminum bushings with the 3 large washers from the Steeda differential pinion kit between the pinion and IRS assembly does work great.

I daily drive my 03 and last year I drove 8k miles so that would be around 2k miles. My car has full open track set-up short of replacing the K-member itself there is no rubber left, KB @ 17#, and Nitto555R 315 drag radials.

On the track you differential is going to get much hotter and will cause them to fail much faster. If the pinion bushings do fail your chances of breaking the differential cover will go up dramatically.

 

[03Cobra745]

So, should I just return all of these urethane bushings and just stay with the rubber until I can get Delrin bushings? :??:

 

[OLD FART]

The KB aluminum bushings with the 3 large washers from the Steeda differential pinion kit between the pinion and IRS assembly does work great.

Did you notice an increase in the noise transfer from the
diff to the body when you changed to the aluminum
bushings? Is it too annoying? Thanks for sharing your
experience:beer:

 

[OLD FART]

Sorry, my last post was directed to toofast4u
Thanks again.

 

[toofast4u]

Originally posted by bhartman
So, should I just return all of these urethane bushings and just stay with the rubber until I can get Delrin bushings? :??:

I wouldn't install or recommend the urethane differential pinion bushings in a car knowing what I know now. You want to get the aluminum bushings for this location or leave them alone. There is also a bushing that connects the cover to the IRS assembly in a very unusual and awkward configuration. This bushing should also be replaced and the best solution I have seen so far uses Delrin at this location which I also have. I have not installed the Delrin differential cover bushing yet as you have to drop the differential to install it so I am waiting for the MJ differential brace so I can install it and a Torsen T2R at the same time.

 

[toofast4u]

Originally posted by OLD FART
Did you notice an increase in the noise transfer from the
diff to the body when you changed to the aluminum
bushings? Is it too annoying? Thanks for sharing your
experience:beer:

The only noise increase was a more pronounced clunk when going into gear. The clunk is due to the fact you are removing the compliancy from the stock driveline so when you go into gear there is nothing left to absorb the energy. Other then that there was no increase in noise that I attribute to these bushings on my car. I have spoken with several people and they did experience a significant increase in gear noise when used with a gear drive differential specifically the Torsen T2R. This is a track differential so if you are using the stock clutch style differential this should not affect you.

 

[Oxford Snake]

I noticed my stock differential bushings were shiny and glazed on the tops and bottoms and the centers were slightly melted. I installed the Steedas as I had already ordered them before I heard of delrin. Still working on those damn control arm bushings.

 

[toofast4u]

Originally posted by Oxford Snake
I noticed my stock differential bushings were shiny and glazed on the tops and bottoms and the centers were slightly melted. I installed the Steedas as I had already ordered them before I heard of delrin. Still working on those damn control arm bushings.

How much have you finished? The removing the LCA bushings is a real PIA and I think probably worse then the IRS assembly bushings due to that damn inner steel sleeve. The UCA bushings are cake they are not even bonded to the steel shells.

 

[Oxford Snake]

Originally posted by toofast4u
How much have you finished? The removing the LCA bushings is a real PIA and I think probably worse then the IRS assembly bushings due to that damn inner steel sleeve. The UCA bushings are cake they are not even bonded to the steel shells.

Not much. I have the entire IRS in the middle of my garage with both sets of control arms removed. The differential and the upper control arms have the new bushings. Started on one IRS subframe and have one lower control arm bushing out. I am going to need to replace the drivers side balljoint as I tried to remove it with a hammer and ended up screwing up the threads. Are the ball joints on the Steeda website that are stock on the 00R the same as the 03? I also screwed up the lower passenger side hub bearing. The rubber seal has a split in it.

 

[toofast4u]

Originally posted by Oxford Snake
Not much. I have the entire IRS in the middle of my garage with both sets of control arms removed. The differential and the upper control arms have the new bushings. Started on one IRS subframe and have one lower control arm bushing out. I am going to need to replace the drivers side balljoint as I tried to remove it with a hammer and ended up screwing up the threads. Are the ball joints on the Steeda website that are stock on the 00R the same as the 03? I also screwed up the lower passenger side hub bearing. The rubber seal has a split in it.

Yes, our ball joints are the same as the 00R. Lthl screwed up one of his tie rods also and had to order new ones so ordered the 00R part and they were exactly the same. Make sure it comes with the crown nut. I had a problem and screwed up one of my front crown nuts when replacing my LCAs and trying to find a new one was almost impossible. I went to several places included 2 Ford Dealerships and nobody had them. I then said screw it and tried to buy the front tie-rod thinking it came with the crown nut and when the guy came out with it there was no crown nut. My father finally found that NAPA had 2 on his way home from work and I told him to buy all three so I now have a spare.

 

[SVTCobra2001]

[email protected] is not longer a valid contact email. Just recieved a bounce from Comcast saying it is not thier customer..

 

[13 Cobra Toy]

Originally posted by SVTCobra2001
[email protected] is not longer a valid contact email. Just recieved a bounce from Comcast saying it is not thier customer..

Try it this way.....

[email protected]

:beer:

 

[SVTCobra2001]

Originally posted by 03 Cobra Toy
Try it this way.....

[email protected]

:beer:

I will give that one a shot.. Thanks