Quick question-Steering rack bushings-aluminum or Delrin?
07-06-2012, 05:59 PM
#1
Three Wheelin'
Thread Starter
Quick question-Steering rack bushings-aluminum or Delrin?
Has there been a general consensus on the best steering rack bushings? It makes sense to me that obviously the aluminum ones would be the best for longevity, however i'd be a little concerned on the abrasion chewing up the steering rack bushing boss's. Should a high pressure lithium based lubricant be applied to the aluminum ones before installation?
Or, are the Delrin rack bushings a better bet?
Or, are the Delrin rack bushings a better bet?
07-07-2012, 03:26 AM
#2
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
No lubricant on the aluminum since no movement is planned. Delrin will be quieter in the steering wheel and can be easier to install. But... Delrin does cold flow under extreme pressure. Not a problem on street cars but maybe big stcky tires and high speed corners might show a problem.
07-07-2012, 03:28 AM
#3
Archive Gatekeeper
Rennlist Member
Rennlist Member
Aluminum on one car, delrin on the other. Happy with both/either.
07-07-2012, 09:09 AM
#5
Rennlist Member
Just finished mine last month. Used Roger's Derlin. I just love them and would reccommend them to everyone. No noise, no movement, just good solid feel.
Good luck,
Good luck,
07-07-2012, 10:09 AM
#7
Rennlist Member
The problem is that the rack mounting foot is only machined on one side, and neither aluminum nor Delrin deals gracefully with the variations in thickness. Also, Delrin does flow a little over time so I am not sure the bolts are staying tight.
I took a different route, and designed a bushing that mimics the function of the factory bushing. The mounting bolt torques against a steel sleeve, and the rack is supported by a combination of Delrin and urethane. I've got a set in each of our cars, the GT with about 40K miles on them.
More pictures and a good discussion on rack play in general is here:
https://rennlist.com/forums/928-foru...ml#post7202909
I talked to a couple of the vendors but the feeling was that the market was well covered.
I took a different route, and designed a bushing that mimics the function of the factory bushing. The mounting bolt torques against a steel sleeve, and the rack is supported by a combination of Delrin and urethane. I've got a set in each of our cars, the GT with about 40K miles on them.
More pictures and a good discussion on rack play in general is here:
https://rennlist.com/forums/928-foru...ml#post7202909
I talked to a couple of the vendors but the feeling was that the market was well covered.
Trending Topics
07-07-2012, 11:30 AM
#8
Three Wheelin'
Thread Starter
So the issue you are describing is that the bushings only have one shoulder so therefore there could still be axial play as everything heat cycles?
Your bushings are very similar to the Porsche ones, i guess it still stands to reason that many 928 parts were designed way too well to be improved upon by a couple of 928 parts vendors with some or no engineering background.
Case in point, the Delrin and/or aluminum solid bushings do seem to get fairly good reviews by everyone on here that has them installed, and that the steering feels much tighter. Although one could easily say "but for how long".
Your bushings are very similar to the Porsche ones, i guess it still stands to reason that many 928 parts were designed way too well to be improved upon by a couple of 928 parts vendors with some or no engineering background.
Case in point, the Delrin and/or aluminum solid bushings do seem to get fairly good reviews by everyone on here that has them installed, and that the steering feels much tighter. Although one could easily say "but for how long".
07-07-2012, 12:56 PM
#9
Rennlist Member
So the issue you are describing is that the bushings only have one shoulder so therefore there could still be axial play as everything heat cycles?
Your bushings are very similar to the Porsche ones, i guess it still stands to reason that many 928 parts were designed way too well to be improved upon by a couple of 928 parts vendors with some or no engineering background.
Case in point, the Delrin and/or aluminum solid bushings do seem to get fairly good reviews by everyone on here that has them installed, and that the steering feels much tighter. Although one could easily say "but for how long".
Your bushings are very similar to the Porsche ones, i guess it still stands to reason that many 928 parts were designed way too well to be improved upon by a couple of 928 parts vendors with some or no engineering background.
Case in point, the Delrin and/or aluminum solid bushings do seem to get fairly good reviews by everyone on here that has them installed, and that the steering feels much tighter. Although one could easily say "but for how long".
In the factory setup the bolt tightens against the steel sleeve which in turn is sandwiched between the crossmember and lower plate. The rack foot is attached to an outer sleeve and floats in rubber. The as-cast surface doesn't matter.
I retained the steel inner sleeve and replaced the rubber with Delrin, and then used a urethane spring-washer on one side to deal with the as-cast top surface of the mounting foot. So the machined surfaces mate with the Delrin, and the cast surface mates with the urethane washer.
This is not meant as criticism of the Delrin or aluminum bushings, they work fine and are reasonably priced. I just wanted something a bit different.
Cheers,
07-07-2012, 01:22 PM
#10
Sharkaholic
Lifetime Rennlist
Member
Lifetime Rennlist
Member
That is an elegant solution Jim! I've got both the one piece aluminum and the two piece delrin and I can see why you went with that. No vendor wants to pick those up?
07-07-2012, 01:54 PM
#11
Three Wheelin'
Thread Starter
As he stated i think that between the aluminum and Delrin ones, the competition would be too fierce. Plus there'd also probably be a littany of threads started about the 3, and an equal littany of arguments about which one is best.
I think i'm going to go with the aluminum ones for their simplicity and longevity.
I think i'm going to go with the aluminum ones for their simplicity and longevity.
But they fit good and look nice.
