'03 Cobra IRS with aprox 40K miles...clunk gone!!!

[Jonny00GT]

I just put Poly bushings on both the front and rear of the Diff. I was surprised to see the rear mount stock rubber bushing worn almost completely through with so few miles!! I had to drop the diff anyway, so I went ahead and tightened up the backlash to .008-.009 while I was at it. Took it for a drive and there was no clunk! Lovin' it!! Just thought I'd share.

-Jonny

 

[ac427cobra]

I just put Poly bushings on both the front and rear of the Diff. I was surprised to see the rear mount stock rubber bushing worn almost completely through with so few miles!! I had to drop the diff anyway, so I went ahead and tightened up the backlash to .008-.009 while I was at it. Took it for a drive and there was no clunk! Lovin' it!! Just thought I'd share.

-Jonny

I'm not surprised one bit that the new poly is a hell of a lot better than your OEM "shot in the ass" rear diff support mount. :-D

I'm curious why more Termi owners don't read this?! :idea:

http://www.svtperformance.com/forums/showthread.php?t=260665

FWIW

:thumbsup::coolman::beer:

 

[Kevin the Clean 1]

I'm not surprised one bit that the new poly is a hell of a lot better than your OEM "shot in the ass" rear diff support mount... :-D


FWIW

:thumbsup::coolman::beer:

I agree Bruce, the diff bushings make a huge difference. As soon as my finals are over (yes I'm a student with a COBRA), I'm re-sealing the diff, upgrading the rear IRS subframe bolts to the 14mm & also upgrading the diff bushings... ! That should take care of the annoying & dreaded clunk. :beer:

 

[Kevin the Clean 1]

I just put Poly bushings on both the front and rear of the Diff. I was surprised to see the rear mount stock rubber bushing worn almost completely through with so few miles!! I had to drop the diff anyway, so I went ahead and tightened up the backlash to .008-.009 while I was at it. Took it for a drive and there was no clunk! Lovin' it!! Just thought I'd share.

-Jonny

Glad to hear that the annoying "clunk" in your car is gone... ! ;-)

 

[ac427cobra]

I agree Bruce, the diff bushings make a huge difference. As soon as my finals are over (yes I'm a student with a COBRA), I'm re-sealing the diff, upgrading the rear IRS subframe bolts to the 14mm & also upgrading the diff bushings... ! That should take care of the annoying & dreaded clunk. :beer:

Kevin:

The larger bolts go in the front subframe mouting locations not the rear! :-D

 

[TrickStang37]

hey bruce, how many miles would you say the delrin bushings should last? just a ballpark estimate.

 

[ac427cobra]

hey bruce, how many miles would you say the delrin bushings should last? just a ballpark estimate.

Well, that depends on quite a few factors. #1 would be, how well was the original installation lubricated at assembly? The later versions of the Gen I bushings sets had a grease groove machined into the lower bushings. The installation instructions advised to fill that cavity with grease at assembly. #2 would be, does the car get driven in all sorts of conditions? Rain, snow, salt, dusty roads? That will decrease life. #3 would be, does the car see open track or racing type events? This puts a lot of pressure on the bushings and will decrease their life.

There is no defined or set time frame to be honest. IMHO you will start to see play from the upper control arm bushings first because they are the smallest diameter bushing and will wear the fastest. You will have to jack up the car and feel the wheel for play.

The Gen II bushings are designed a little differently and grease fittings have been advised for them for quite some time now. I even offer grease fitting kits as well. With the new kits and proper lubrication, the Delrin control arm bushings should last a lifetime. There should be virtually no wear if properly lubicated.

FWIW

 

[SlowSVT]

Bruce

I have the MM Delrin bushing kit installed in my car and noted an "issue" with the UCA bushing. The eyelet they side into is not very wide and the OD of the bushing made for a light press fit. Once the bolts were tightened up the bushing would just rotate in the UCA and not the crush sleeve. That made the outside of the delrin bushing act as the bearing surface riding on the narrow eyelet which will wear the OD of the bushing out quite quickly.

To secure the bushing I applied the adhesive "Goop" to the outside of the bushing and the bearing bore in the UCA and re-installed the them. I am not sure if MM undersized the bushing OD or if they are intentionally made that way. The narrowness of the UCA bushing eyelet doesn't help either. Goop it a pretty aggressive adhesive and has an incredibly strong bond and should hold them in place. "pinning" them in place is another possibility

I'm not sure if this is the case with your bushing but it is something that can or should be considered if they run across this problem. May be good for added insurance.

 

[Kevin the Clean 1]

Kevin:

The larger bolts go in the front subframe mouting locations not the rear! :-D

Ooops... ;-)

 

[black 10th vert]

SlowSVT, not sure if this is your issue, but maybe when you did the light press fit it made the id of the bushing into an interference fit, so that it would need to be reamed, or the steel stleeve would need to be lightly turned/polished down a bit. The other thing that causes this is when the sleeve is not quite long enough, so that when torqued, the mounting ears deform slightly, which puts pressure on the delrin/poly, instead of the sleeve. I've had this happen several times doing various suspension upgrades on my FFR Cobra replica. You can make shim washers out of some tubing that matches the od and id of the sleeve to resolve that, or face the delrin bushings a bit, whichever is easier for you.

hope this helps!
Brian

 

[ac427cobra]

Bruce

I have the MM Delrin bushing kit installed in my car and noted an "issue" with the UCA bushing. The eyelet they side into is not very wide and the OD of the bushing made for a light press fit. Once the bolts were tightened up the bushing would just rotate in the UCA and not the crush sleeve. That made the outside of the delrin bushing act as the bearing surface riding on the narrow eyelet which will wear the OD of the bushing out quite quickly.

To secure the bushing I applied the adhesive "Goop" to the outside of the bushing and the bearing bore in the UCA and re-installed the them. I am not sure if MM undersized the bushing OD or if they are intentionally made that way. The narrowness of the UCA bushing eyelet doesn't help either. Goop it a pretty aggressive adhesive and has an incredibly strong bond and should hold them in place. "pinning" them in place is another possibility

I'm not sure if this is the case with your bushing but it is something that can or should be considered if they run across this problem. May be good for added insurance.

Russ:

The narrow cross section of the UCA has been a challenge. Originally the kit left the metal inner sleeve in the UCA to gain additional support for the bushing. But that limited the diameter of the inner sleeve. I then redesigned the upper bushing because I wanted to increase the inner sleeve diameter and that required the removal of the metal sleeve.

Currently there is about a .005" press on the bushing and that press is compensated for calculating the required diameter for the aluminum Hardcoated inner sleeve.

With the new grease fittings, the life of the Delrin really is no longer an issue anymore.

FWIW

:thumbsup::coolman::beer:

 

[SlowSVT]

SlowSVT, not sure if this is your issue, but maybe when you did the light press fit it made the id of the bushing into an interference fit, so that it would need to be reamed, or the steel stleeve would need to be lightly turned/polished down a bit. The other thing that causes this is when the sleeve is not quite long enough, so that when torqued, the mounting ears deform slightly, which puts pressure on the delrin/poly, instead of the sleeve. I've had this happen several times doing various suspension upgrades on my FFR Cobra replica. You can make shim washers out of some tubing that matches the od and id of the sleeve to resolve that, or face the delrin bushings a bit, whichever is easier for you.

hope this helps!
Brian

Brian

The problem I had was that they were just too loose to begin with. I was expecting a fairly firm squeeze to get them into the UCA but they just slid right in with very little resistance. I noted it but didn't give it much thought thinking for some reason they would tighten up after I torqued up the A-Arm pivot bolts. Articulating the A-Arm I immediately noted the UCA bushing OD rotating on the A-arm bushing bores.

I think using adhesive to bond the upper A-arm bushing in the A-arm should work. I have worked with a lot of adhesive but Goop in particular seems to be very effective.

I don't think Ford had delrin bushings in mind when they designed the UCA bearing eyelets.

None of this bothers me like the IRS rear wheel bearing design :cuss: Who ever signed off on that one should be flipping burgers now.