GTD rod change guide?

Dave Bilyk

Member
GT40s Supporter
#1
Guys, the pic show
20180725_195442.jpg
s the rear guide on my DAX40 rod change to UN1 transaxle. Like a lot of DAX components it could be GTD. Can anyone tell me if it is and where to obtain one? It seems to be a cast in or pushed in rubber with a thin metallic or fibre sleeve that has fallen out so there is too much slop. Thanks
Dave B
 

Dave Bilyk

Member
GT40s Supporter
#3
Hi Ian, this rod is quite a diameter so would need a colossal joint. I have been considering changing to a cable but not sure what to do yet! In the meantime I may find a way round it but wondered if durect replacements were still available.
Dave B
 
#4
Dave B;

If this shift rod is the type that rotates and slides back and forth, you might consider replacing the old bushing with a Thompson linear ball bushing. They are a type of ball bearing that allows rotation as well as translation. They are available in many sizes; I used 3/4" ball bushings in my linkage.
You will need to clean up the shift rod so that it is an accurate 0.750" (or whatever the size that you're using) and also smooth & clean.

Regards, Neil Tucson, AZ
 

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Mike Pass

Member
GT40s Supporter
#5
Most rod systems use machined 5/8” stainless steel rod and 5/8” rose joints. Drop me a message with your email if you want more info.
Cheers
Mike
 

Dave Bilyk

Member
GT40s Supporter
#6
Neil and Mike, thanks for your replies. I see similar linear bearings online at simplybearings and bearingboys, but with the layout I have, the extra dof of the rose joint might be necessary. I'll check it out tonight. I think mine is 0.75", but again I will check.
Dave B
 

Dave Bilyk

Member
GT40s Supporter
#7
The rod change diameter is, wait for it, 0.875" , no wonder it changes like a tractor with around 6ft of it to push back and forth!
Dave B
 
#8
Dave;

If you are using a 7/8" dia solid rod, you can substitute thick-wall tubing with a significant reduction in weight without much reduction in torsional stiffness. If you do use ball bushings, use the Thompson Super Ball Bushings. The "Super" versions allow some angular mis-alignment. The plastic housing versions are light weight, cheaper, and work just fine.

Regards, Neil Tucson, AZ
 

Dave Bilyk

Member
GT40s Supporter
#9
Neil, thanks
I think it is already thick wall tubing, I have removed the section of rod with the bracket and bush attached and will check, I will see if I can make a quick but effective repair while I consider my options. The gear lever rod is also thick, too thick for a gate guide plate, so I ultimately want to fix that too. As a result I need to consider cable change too.
Dave B
 

Terry Oxandale

Skinny Man
GT40s Supporter
#10
I use 14 gauge 3/4" SS tubing for my shift rod on my 930 with no issues on rigidity. The one issue I did have, which not everyone would be willing to deal with is that the tubing was slightly over .75" on OD (not sure why), which meant the linear bearings that I use would not allow it to slide well until I shaved the OD down in the area of travel inside the bearing. An afternoon's worth of work with a metal file, and it came out fine, and will never rust.
 
#11
Terry;

Being oversized on the OD is not uncommon for DOM (Drawn Over Mandrel) tubing. Surprisingly, its tolerances on outside diameter and wall thickness eccentricity are inferior to CREW (Cold-Rolled Electric Welded) tubing. It has superior tolerances on inside diameter, though. The best tubing would be CREW that is re-sized by being drawn through an outside diameter die. But we can't always find what we want, so ......

Regards, Neil Tucson, AZ
 

Dave Bilyk

Member
GT40s Supporter
#12
The bush is marked CLATONRITE B8470 and obsolete. It is a rubber flexible outer part bonded into a tube, and has an inner metal tube slightly over 7/8" with an inner plastic or fibre sleeve, which is the part that has worn thin and fallen out. So I had a look at bushes and tubes I might use and amazingly, found that a copper 22mm (0.866") water pipe solder joint would do. Split it lengthways, drove it into the bush and lapped it in. Back together and working fine! It will do for now anyway until I replace the whole lot. The rod is thick tube btw.
Dave B
 

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Dave Bilyk

Member
GT40s Supporter
#14
Thanks Neil, but alas, my skills are at the low end compared to many others here, lets call it a neat bodge ;)however, I am sure that it will do the job.
Dave B
 
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