Suspension - Nylatron vs. Urethane

Gents, Time to replace the control arm bushings on my TR3. I do not race the car (legally) so for road use only. It seems to me that using nylatron on the upper control arm bushings would decrease deflection and have little effect on ride quality due to their function. The alternative is 'prothane' bushings. Who's done those changes and what were the results?

I know you're going to get a lot of differing opinions, so I'll give my 2 cents worth.

I didn't see much of a difference in ride quality when I upgraded my TR6 to Nylatron, I think ride quality has to do with your spring and shock choice more than anything else. I have yet to find something negative about the Nylatron bushings... the car feels new car tight and has none of the squeaking that can come from poly bushings. The "slop" that the car had before the upgrade in tight manuevers is now gone.

The bushings were a bit of a pain to install, I had to hone my trailing arms out a tad to get them to fit. Nothing hard mind you, just tedious.

Hi,

I've installed urethane bushings on my '62 TR4 and many other cars. In fact, I've got a set in the garage right now, awaiting installation on my '97 Land Rover. I try to avoid rubber replacements, which seem to last only about a year or two. I wouldn't use nylatron on a street car. Just too harsh and noisy for my tastes.

In fact, there are also various hardness or durometer ratings of urethane. It's possible to get urethane that closely mimmicks OEM rubber bushings, but will last a lot longer. Or, you can get something a little harder for more precise handling. I used moderately hard urethane on my TR4, but will be putting softer urethane bushings in the Land Rover.

Ride quality is a consideration. But not a huge one for our ladder-chassis cars because they aren't all that smooth riding to begin with! Road noise is another. Harder bushings will also transmit noticibly more noise.

And, any minor faults or slight looseness in the steering and suspension geometry will be more apparant with harder bushings.

Racers don't care about the noise or harshness of the ride, so will often choose nylatron bushings. In fact, some go even further and use roller bearings (Nadella is one type), even harsher and noisier than nylatron but providing very precise handling and full suspension action. I'd definitely not recommend roller bearings!

My TR4 uses a similar setup to your TR3 and bushing installation was quite easy. There is just a lot of disassembly. One suggestion, do one side at a time to have the other for reference.

Everthing was a slip fit, except for the outer/lower control arm to trunnion joint. While you have everything apart, I suggest replacing ball joints, thrust washers and seals, as well.

The only items I had trouble with were the vertical link to trunnion seals (sloppy fit) and the outer washers that the nut presses onto the splined ends of the trunnion. The new replacements of these latter were simply wrong (ordered three times from two different vendors) and there was no way they would work. I ended up reusing an original set that was in decent condition. Be a little careful removing the originals, just in case you need to reuse them.

I went the extra step of drilling all new joints for cotter pins, and used castle nuts rather than nylock. Many of these joints are too easily overtightened and I didn't trust the nylocks that were provided. If you reuse the original upper/inner fulcrum and and outer/lower trunnion, and their respective nuts, they are probably already set up for cotter pins.

The lower/outer joint is a brass bushing that must be reamed to fit the trunnion, after it is pressed into the control arm. (I've heard that Revington TR in England offers a bushing for this application that doesn't require reaming, but I haven't tried these.) One trick to assembling these is to use some 90W gear oil during assembly, and you'll find they are much more easily greasable afterward. If assembled dry, it's next to impossible to get grease into them via the zerks. Some folks just use a pressure gun and 90W gear oil on these four fittings all the time.

It's a good idea to smear a little synthetic grease on urethane bushings during installation, to help avoid "urethane squeek". Some folks install zerks to allow greasing with a gun later, without disassembly. I've done that on my sway bar bushings, but not on the upper/inner control arms.

Your lower control arms already use nylatron bushings on the inner joint. In fact, if you choose to use nylatron on the upper/inner, I think it would be quite possible to use the lower/inner bushings and sleeves, with a little careful shortening to make them fit properly.

For the lower/inner (and the upper/inner if you choose to use nylatron) I recommend looking for the nylatron bushings with stainless steel sleeves. These help prevent rust in those joints and make the replacement job a lot easier the next time. I also smeared the shafts with waterproof grease or copper anti-sieze to help keep them in good condition.

On the upper/inner joints, be sure to check the shafts of the fulcrum are in good condition. Any significant corrosion or wear there and the whole fulcrum should be replaced, otherwise the new bushings will wear out quickly.

Urethane bushings are also available for the rear leaf spring shackles and I recommend them. Those often wear almost as quickly as the upper/inner joints on the control arms. It's also a pretty easy job, although the original, 40 year old rubber bushing on my TR4 were a little tough to get out. Nylatron is also available for the shackles, but are pretty much considered "race only".

You may already know, please use a good internal spring compressor on the front suspension job. This is an important safety issue.

Once the suspension is back together, the manual and some others will tell you to not tighten some of the nuts fully until the car is back on the ground. I "worked" the suspension by hand before installing springs, shocks, wheels and tires, to get it settled and make sure there was no binding. It seems fine done this way, but I'll go back and check all the joints later after the car has some miles on it.

Lastly, having the outer/lower bushing pressed in and reamed was surprisingly difficult and costly. It took a bit of searching to find a shop here that would do it and they charged me 2 or 3 times what I felt was fair. I hope you have better luck. In the future, I'll buy the reamer and do it myself.

I hope this is helpful.

Cheers!

Alan

Alan, Thanks for the in depth response. It's a pleasure to learn from others experience. I do believe I'll go with the poly. You are correct that TR3's are stiff enough as it is.

Holy schniekee's . Alan, that was awsome, I can't even find a grammatical error /ubbthreads/images/graemlins/laugh.gif

Don't ask Alan the time. He will tell you how to make a watch.

Nice job, Alan.

Bill