View Full Version : Suspension Rebuild ??

07-17-2006, 12:30 PM
I'm planning the front suspension rebuild of my TR4 and wondered if it is necessary to replace the steel bushings. If the old ones look good, can I simply leave them in or is there a reason to replace them while I have it all apart? They look like they would need to go to a shop to have the old ones removed and new ones pressed into the arms and possibly reamed prior to reassembly. Advice is appreciated.

07-17-2006, 04:01 PM

First of all, let's be sure we're talking about the same parts. I'm pretty certain you are refering to the bushings at the outer/lower suspension fulcrum (outer ends of all four a-arms), right?

If so, I've only seen bronze bushings in there and unless they have seen very few miles they nearly always need replacement. After disassembling the suspension, you can check for wear by sliding them back in place on the pin and seeing if you can rock any play, side-to-side. You will usually find some, which means new bushings are needed.

The standard fitment there is a pressed-in bushing that is then honed to exact size (i.e., no detectable play when tested as above, but free to move when greased). I say "standard fitment" because I have heard that Revington TR in England (www.revingtontr.com) now offers a bushing that doesn't require reaming to fit, and might be worth the extra effort and cost. But I haven't tried these, don't see a listing on Neil's website and can't really say if they are good or not.

My experience replacing the standard type not too long ago was not much fun. The LH side was done first and everything was fine. A local auto parts store handed them over to a machine shop that fitted them well for a not-too-ridiculous fee. Cost was $40 for two a-arms, if I recall correctly. IMO a bit high for 10 minutes work, but I could live with it.

For a variety of reasons, installing the RH side was delayed and by the time I got around to it the auto parts store was using a different machine shop that:

1. Initially quoted $160 to install two bushings and wanted to use a drill bit to size the bushings.
2. Finally agreed to $80 (still ridiculous, IMHO) and said they had found a way to ream them.
3. Did the job, but kept my parts for two or three weeks and in the end screwed up one of them by over-reaming it (usable, but just barely)!

Next time, I'll just buy the tools, get the parts and do the job myself. Or order the special ones from Revington TR.

Reamers can be a little hard to find, but www.harborfreight.com (https://www.harborfreight.com) and www.eastwoodco.com (https://www.eastwoodco.com) both seem to offer sets of adjustable ones that I think might work. I haven't bought a set and tried them yet, so can't be certain if they'll do the trick. HF is quite a bit cheaper than Eastwood, not surprisingly.

Hope this helps!


07-17-2006, 05:17 PM
One of the few tools I acquired from my father included a full set of adjustable reamers. They run from 15/32" to 1 1/16". I only use them two or three times a year, but when you need them, there is no substitute. When I did the the job on my TR3, the bottom trunnion where the A-Arms attach showed a little wear. I trued them up, but each peg turned out a slightly differnet size. With the adjustable reamers, I was able to get a perfect fit on each one. Needless to say, I am the official bushing fitter for the local Triumph club.

The problem with "exact fit" bushings is that the press fit might be inconsistent, and the mating pieces, even if new, might not be and "exact size". We run into this at work all the time when fitting bushings on starter noses. They can be had in various sizes to accomadate armature shaft wear, but they will press into the noses tighter or looser depending on the bore of the nose. Then, if you get a batch from a different vendor, all bets are off. What we do now is gauge the shaft size (three sizes) and press the appropriate bushing into the nose. Then the bushing gets roller burnished, which is a form of reaming. Perfect fits all the time.

07-18-2006, 07:09 AM
Sounds like the price of an adjustable reamer set from HF is about the same as having a shop do the job, maybe less, so I can try the job myself and have the set on hand for the next effort. The metal bushings are cheap so it won't hurt if I ruin them. I think I'll give it a go myself. Thanks for the input.

07-18-2006, 12:56 PM

Not trying to talk you out of it, but before buying a set of reamers you might check into machine shop costs in your area. I live in Silicon Valley, where everything is expensive.

Plus, an experienced, old-timer in a machine shop who has done this sort of work before would know it's less than an hour's work to do all four. I think the silly costs I encountered were influenced by a less-than-knowledgeable shop.

Finally, I'd suggest you take a rough measurement of the inside diameter of the bushing (or the OD of the pin it fits onto) to be certain the set of reamers HF is offering covers the range you need. My car is assembled now, so I can only guess at what size might be needed (anyone know for sure?).

The larger Eastwood set appears to be the pretty much the same as the HF set, although twice as expensive. The smaller, less expensive Eastwood set covers a smaller size range, that apparently is not available from HF.


07-18-2006, 01:22 PM
The HF set starts at 15/32" (.469) and goes to 1 1/2". Plenty of coverage there. That's where my set starts, and I had the right size in the set. IIRC the nominal size for that bushing is 5/8". For the sixty bucks HF gets for that set, you'd be hard pressed to find a machinist that would mess with this for much less money.

07-20-2006, 07:45 AM
I'm on the road right now (and missing the Dallas VTR convention /ubbthreads/images/graemlins/mad.gif) so can't show you pics, but I did a full rebuild just a couple of months ago including replacing the bushings.

Once you get the suspension apart I think you can check for excessive play with the trunnion and the lower arms - in my case the play was not noticeable by me on the car but when separated it was obvious that new bushings (as well as trunnion) were needed.

I rigged up a bolt with washers to remove the old bushings - worked slick, and pressed in the new ones with my bench vice. In my opinion, a shop isn't really needed for the operation though you do need to be careful.

Reaming was probably the most difficult operation, but not a lot of material is removed. I bought a cheap non-adjustable reamer (brain can't remember web link source but I can provide if needed) and did it myself. I embarassingly chucked it in a hand drill and reamed them manually on my bench vice as I don't have a drill press. Worked well for 3 of 4 bushings, but on the 4th I got sloppy and did not center the reamer well - had to buy another bushing to fix the mistake. A proper drill press, or better yet a machine shop would prevent that problem. The end result though was bushings that were centered and fit well on the trunnions, even though it was a by hand operation.

Anyway, if you want me to post pics or describe anything this weekend when I'm back at home just respond to this thread and I'll do so.


07-20-2006, 11:32 AM
I plan to do exactly what you did so all the information and photos you can offer would be greatly appreciated. Where you got your reamer would give me the choice of getting just the size needed or an adjustable set. I have new shocks, springs, trunnions, stub axles, vertical links, ball joints, wheel bearings and the poly bushing kit. Is there anything else you would recommend replacing with a new part or any other area to restore while I'm doing the suspension? I have already replaced the rear suspension with new parts. Your experienced advice is greatly appreciated.


07-23-2006, 10:43 AM
Okay, I'm back and I've cleaned up a couple of pics that may help. Unfortunately I didn't take as many shots as I thought so I'll have to just describe a couple of things.

First, bushing removal. To make it easy, the key is to rig up a mandrel to push out the bushing. Here is a pic of the fancy mandrel setup:


It is just a stack of washers that are sized to push out the bushing, but fit in the bore of the arm. I made a couple of these, the short one to start the process, and then switched to the long one to finish. Note in the pic also is an example of a pretty worn bushing - in my case it was an obvious candidate for replacement.

I bought washers in bulk at my local TSC store and they happened to be a perfect size: 0.743" or there abouts outer diameter. I'm sure you can find them, but if you can't, pm me your address and I can probably mail you a couple of them pretty easily.

With the mandrel, I pushed out the bushings with my bench vice. Sorry, no picture on that one, but it is pretty simple: mandrel on one side, oversized socket to receive the bushing on the other side and tighten the vice to remove.

One bushing was very tight and I really couldn't get it to budge with my vice, so I tried a 2nd method which worked well, and I do have a picture:


For this, use the same washers on one end, the socket on the other, and a long bolt and nut to hold everything together. Put it on the ground, tighten the nut and the bushing finally releases. This method only works to break free the bushing, but the bolt head eventually draws into the arm so you can't completely remove the bushing. Once you get the bushing started though you can complete removal by putting it back in the vice.

On to bushing installation. Pretty easy, use the bench vice, make sure the bushing is square to the arm, and make sure the hole in the bushing lines up with the grease fitting:


I used a flat washer against the bushing to make sure I didn't mar anything.

Finally, reaming. I bought a fixed chuckable reamer from Enco. 5/8" HSS, pn 331-1140 cost $13.95 plus shipping. They have a good website and ship quickly. I did have to grind it down a little to fit in my 1/2" chuck:


Basically a little cutting oil, slow rpms and careful feeding of the reamer into the arm held by the bench vice. I didn't take a picture of the operation but it would have been pretty embarassing to show the jury rigged setup. I carefully did 3 of 4 and was very happy with the results. I rushed the 4th and wound up reaming off center and had to order a replacement.

In the end though, the bushings fit the trunnion with a little play evident but overall I was pleased with the final fit. If I were to do it again, I would consider buying one or two adjustable reamers from Enco (Size B&C about $35 combined plus shipping). Start the reamer completely undersized and slowly expand until you get a perfect fit.

Hope that helps,

07-23-2006, 06:08 PM
Great info Randy!

This should be copied over to the maintenance articles here on BCF!


07-24-2006, 07:03 AM
This helps tremendously. Thanks soo much for your efforts to post. I owe you /ubbthreads/images/graemlins/thirsty.gif


07-24-2006, 07:54 AM
Thanks for the feedback guys, glad to help.

As you can probably guess, I am one of those 'frugal' types and I'm happiest when I've spent the least to fix something. If you want a perfect fit on the bushing, don't go my route with the fixed reamer - get adjustable. But you can still be 'frugal' if you just buy a couple of the adjustable reamers from a place like Enco!


08-05-2006, 02:40 PM
I'm in the midst of a front suspension rebuild for my tr4, and this has been very helpful.
I've encountered one problem that I don't see discussed: The trunnion pins that the lower a-arms attach to (the ones for which the bushings are reamed to fit) on my car measure 0.624 in the horizontal direction and 0.617 in the vertical. Is that excessive enough to replace the trunnion? Is it possible to replace just the trunnion pins? Since it's in the vertical direction, it should only produce play in the plane of the wheel travel anyway, but it may also result in accelerated wear of the new bushings.
Any thoughts/help?

08-05-2006, 07:54 PM

That sounds like a lot of difference - .007" - perhaps a lot of play, but I don't have the specs handy.

I believe the pins can be replaced, a few places in England seem to sell them separately, I don't see anyone in the U.S. offering them. However, I gotta comment that it seems a job for a machine shop with very heavy duty press equipment and I'd be concerned that something might get damaged in the process. So the last set I did, I just bought a pair of set up trunnions, with brand new pins already installed.

I gotta say, the next time I'd be very tempted to change to TR4A trunnion setup with the removeable bolt, all of which is more servicable. It would mean more parts to buy initially, but the trunnions themselves were about half the price of the earlier type, last time I looked. Might work out pretty close to the same cost, in the end, but that change would eliminate the fussy bronze outer a-arm bushings that require honing, too.


08-05-2006, 08:46 PM
Wear on my trunnions was also vertical - there was enough wear and play in the old system that a shoulder had built up on the trunnion pins which made changeout an easy decision.

If you are trying to stay original, my guess is you could be okay as is (just a guess) - but expectation would be earlier play buildup in the trunnion over time. For these cars now, that may not be a big deal.

As Alan said, the pin replacement is potentially possible but it would not be easy. I bought replacement trunnions at TRF and I'm happy with their quality - seemed liked pretty faithful reproduction parts when compared to the originals, including holes drilled for cotter pins. I was lucky to get them on sale earlier this year at $45 each, right now they are about $90 each.

One part I would not get again at TRF is the thrust washer for the trunnion - the ones I received were actually thinner than my original worn ones. They could have worked as is but the problem was when I put everything back together the thinner washers made the castle nuts thread on trunnion pins too much, to the point of almost missing the locking cotter pin. I bought replacements from Moss and they were much better.

Not sure I agree with Alan on the feasibility of using a TR4a setup on the TR4. The inner mounts are different, so the lower a arms will be different, the vertical links are different, etc. - even if it bolts together you may not get the geometry right and there is no camber adjustment with these TR4s.


08-06-2006, 02:54 PM
I was lucky to get them on sale earlier this year at $45 each, right now they are about $90 each.

[/ QUOTE ]

That's a great price. The 4A trunnions regularly sell around $50.

Not sure I agree with Alan on the feasibility of using a TR4a setup on the TR4. The inner mounts are different, so the lower a arms will be different, the vertical links are different, etc. - even if it bolts together you may not get the geometry right and there is no camber adjustment with these TR4s.

[/ QUOTE ]

Hi Randy,

It's actually a more common mod than you might think. Lower a-arms are the same on all TR4/4A/250/6 - except for very, very early TR4 to approx. CT6500 that had 0 caster just like TR2/3 - and can be used with either inner mounting method. Just a change of bushings is needed. Vertical links are also the same on TR4 after about CT6500, all the way through TR6. Upper a-arms are also the same throughout this range. One thing that's different is the steering tie-rod brackets, these changed first when TR4 went to 3 degrees of caster, and again with the later TR4A rack and pinion setup (actually in mid-TR4 production). There were some minor differences in the disc brake dust plates, too, but they are still pretty interchangeable.

You are correct that using TR4A-6 outer suspension component still will not provide any convenient adjustability of the camber. But, you would be no worse off in that respect, since TR4 (and TR2/3) have no direct means of adjusting camber anyway.

There are several ways to get some camber adjustment:
1. Remove the inner horizontal pin and weld TR4A mounts (well reiniforced, not the original weak type) onto the frame rail, to allow for adjustement with shims just like TR4A-6.
2. Replace the upper fulcrums with adjustable, such as those offered by Revington TR.
3. Shorten the crosstube/brace between the spring towers, pulling the suspension together at the top.
4. Shorten the upper a-arms.
5. Bend the vertical link.
I've seen all these methods done. Some work better than others. Any that change the length of the upper or lower arms is more likely to lead to bump steer or other issues, that will probably need further work to sort out. Caster can be fine-tuned a little at the same time, with most of these methods.


08-06-2006, 03:25 PM

Good information. I've never seen all the parts side by side so was very leery that this was not possible.

I'd be interested to do a direct comparison on the lower trunnion on the 4a-6 to the 4. I know the later TR6 setup has a vertical link that is different - the grease fitting is on the vertical link instead of the trunnion, and the axle stub is higher relative to the start of the trunnion threads on the TR6 versus the TR4. That lead me to think it would be quite a difficult changeover.

It'd also be good to look at the lower wishbones, I'm not clear, for example if the TR6 bolt and bushing setup fits as an exchange for the pressed in bush and ream bushings on the TR4. If it is that would be a big improvement.