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Sunday, September 4, 2016

Triumph Spitfire Chassis Restoration #6 - Amended

I only got two days at the garage since my last post, though, so the work was not all that great. Lots of ends and ends, however, so I'll get to it. Also, some of the pictures are a bit on the blurry side. Not sure if it's the lighting or what, but I'll work on that in the future.

Tying up loose ends from the last post, I received my two cans of Signal Red from Automotive Touchup, but did not try them out yet.

I got a pretty quick response from Rimmer's regarding the plugs for their grease-able u-joints. I was correct about the u-joint being metric while the plugs were standard. They have since deleted the association on their website that lists the plugs as fitting the u-joints. I was able to source a few plugs from my local True Value and they work just fine.

I ended up placing my part order with SpitBits, instead of Rimmer's, since it's been a while since I threw Nigel some of my money. I wasn't in a hurry for anything this time around, and the exchange rate didn't really give me that much of an advantage with the international shipping, so I went with him. I got two new rear trunnion kits, since he does NOT carry the Powertune brand that I had problems with and a new brake line kit that I forgot to get from Rimmer's with my last big order. There were a few more odds and ends, of course, but those were the major things.

My calipers were in pretty sad cosmetic shape with quite a bit of rust that I could not adequately get at without splitting them apart. So, I made the mistake of breaking them apart. Turns out they are not really supposed to be split after they are manufactured. Of course, asking about it on my favorite forum ran the gamut of "you'll need to buy new ones now" to "we used to do it all the time". Thankfully, the rubber seals that seal the two halves are still available (easiest place I found to order them was from Moss, with an un-illustrated part number of 583-820).

I did find an old twist-tie in the bleed screw hole of one that some PO put there at some point, so I guess it was good that I split it, at least for this one.

The twist-tie I found in the bleed screw hole.

The two halves. The black ring on the left-side half is the seal that's to be replaced.

Another mystery surrounding this is there is no available torque spec on the two bolts that hold the caliper halves together. It took a 3/8" breaker bar and a vise to break them out, so I'd say that's pretty darn tight. Also, one bolt's threads got a bit galled when removing one, so I took care of that.

Unbeknownst to me before this, there is something called a thread restorer tap and die set. Unlike a "normal" tap a die set, this set isn't designed to actually cut threads, but dress them up. Thinking this would be the perfect way to repair this bolt and I'm sure many more as the restoration continues, I ordered a coarse and fine thread set from Amazon. It worked, so I can only say I recommend it if you find yourself in a similar situation. I took some pictures of this, but they turned out pretty badly. Suffice it to say that the bolt would not thread into the caliper before I "restored" them, and screwed in like butter after.

Next, I took the calipers to my 6" bench grinder with a brass wire wheel. It was hard to get in all of the areas, but it worked out pretty well. I chose brass because I didn't want to remove any metal and I intend to use it for bolts and nuts and the like as well.

Caliper halves after a long soak in Purple Power, but before the brass wheel treatment.

After the brass wheel treatment. Oooooo, ahhhhhh.

After cleaning them up, I shot them with three coats of Clear VHT Caliper paint. I didn't want them to have a color, so I decided on clear to prevent the rust problems that I just got done correcting. I taped off the mating joints between the two halves and the piston cylinders.

Once the painting was done, I put in the new rubber seal for the half that used it.

The recess for the rubber seal (left). The other hole is where one of the two bolts holding the halves together goes.

The seal installed. Not much to it. It's thick for it's size and squared-off, vice round like a regular o-ring.

I also put in the rebuild kit including the internal and external piston rubber seals. It was much easier, with the caliper in half, to get the external seals done properly. I did these for the first time a long time ago and they kicked my butt.

Internal piston seal. Obviously, I was unable to get ALL of the rust off. A bit of damage to the lip, too.

External rubber seal, on the caliper lip. The piston also has a groove that accepts the other end of the rubber seal.

Sorry it's blurry, but this shows the piston and rubber seal mating.
Once the seals were in, I bolted the two halves together, but was running out of time and didn't tighten them down.

Mostly finished. The other bleed screw is there as a foreign material exclusion.

Another thing I got done was the rear spring refurbishment. I blasted, primed and painted the smaller leaves that would fit in the blasting cabinet and took a wire wheel to the two largest. New spring thrust buttons were used. There is discussion on the "original" style rubber buttons that compress and squish when they are loaded and others that are made of teflon (or nylon, maybe). Because I couldn't source these conveniently and I frankly didn't think it would really matter all that much, I stuck with the rubber buttons.

Top and side view of the spring button. About the size of a nickel, I used a dab of grease to hold them in place during leave assembly.

I also cleaned up the small bolts/nuts that hold everything together. Finally, new bushings rounded out the job.

Before (right) and after taking the brass wheel to the small bolts of the spring assembly.

I used a c-clamp to hold everything together while tightening down that center nut. The top is rounded, so pliers were required to get it tight.

Pressing in the bushings. Anti-seize for all my friends! The bulge you see towards the end of the leaf is the recess (on the other side) for one of the thrust buttons.

The finished product. A comment on my favorite forum was that is was a very tall arc. Guess we'll see when I try to install it.

Next up was replacing the inner axle seals as part of the differential refurbishment. This was a simple job. This is the differential out of the black car and while it didn't have the mass of grease and grime that the Dot's differential did, I figured replacing the seals, and the main pinion seal, was a good idea. The bearings felt good all around so they are not getting replaced.

Here's how the assembly fits together (picture courtesy of Rimmer Bros.)

New seals on left, old on right. New ones seems to be all rubber while the old seems to be a rubber/fabric mesh.

The seal driven in to the oil seal retainer. I used a piece of wood and rubber mallet to ensure it went in evenly.

Bearing puller, working in reverse to "draw" in the bearings. Went on smoothly.

I came up with a novel way to get the circlip re-seated into its groove. This circlip is just a piece of spring steel with no spreading tabs like a "normal" circlip. I didn't want to take a flat head screwdriver to it and either damage it by bending it up too much or scoring the driver shaft. So, instead, I used the closed end of a combination wrench that was just big enough to fit down the shaft, but small enough to not go over the circlip. A quick hit on the wrench with a hammer popped the circlip into place. Sometimes, you have a moment of "I'm all that and a bag of chips" in your work. This was one of those. It's the little things.

Using the closed end of a combination wrench to drive the circlip down into its recess to retain the bearing.

I did order new circlips for this from Rimmer's. Another data point where I got what I consider the wrong part. The new ones were much bigger diameter than the originals. I verified that I ordered the correct part. The old ones were fine, I just figured new ones were cheap insurance. Like the plugs for the u-joints, these are too inexpensive to send back but, like I said, are another data point. I did some quick research and I think the axle shaft diameter may have changed at some point, necessitating larger circlips. SpitBits lists the ones I've got as only good for Mk3 and up. I've emailed Rimmer's and I'll see what they have to say this time.

Original on top, "new" ones on the bottom.

That was about it for the day. We have a hurricane coming to visit on Monday so since the weather will be terrible, I'm going to go to the garage to celebrate the Labor Day holiday. I should be able to get the other brake caliper put together and both fully tightened down. I'll also work on putting the differential back together as well. Until next time...

I got about 5 hours in the garage today. Doesn't seem like I did too much, but I did accomplish a few things. I got the calipers all done and bolted back together. I decided to torque them to 80 ft-lbs, which is where my torque wrench tops out.

I also brought the RH rear vertical link to the garage from my attic to refurbish that to use instead of the one I already cleaned up due to a missing spacer that I didn't notice. Unfortunately, the other one is missing both trunnion spacers (well, they are welded, but are more like washers). I've asked on my favorite forum for recommendations, including the option for a new one (to me) if need be.

Spacer should be on the right like it is on the left.

After stopping that job short, I moved on to getting the bushings out of the rear differential. What a pain. I was able to use my propane torch to burn on the inner bushing and rubber, but the outer collar was one with the differential case. Since it was so thin, I couldn't get anything to smack on it good. Instead, I took my sawzall and cut the collar down to the differential house. I then took a chisel punch and worked at it. Eventually, after enough beatings, they both slowly came out.

The beatings will continue until morale improves...or the bushing comes out. Marred up the differential case a bit, too.

The bushing removed.

Once the bushings were out, I put the case in the blaster and cleaned it up pretty good. I didn't spend a lot of time on it since it's not that visible. I also blasted the front mounting brackets, but didn't get any pics of that. I sprayed them both with one coat of primer. The wind from tropical storm Hermine was really picking up by then and the painting was challenging to say the least since I don't want to do it inside if I can help it. So, only one coat to prevent flash rust on the freshly exposed metal.

Just the back half.
I'm not quite sure how I'm going to attack the other half of the differential. You know, the one with the big gears in it. I definitely do not want to remove all of that stuff because there are tons of measurements and shims and the like that I just don't want to mess with. Probably the easiest would be to clean up the gear half as good as I can (no blasting, of course), but it all back together and a prime and paint it as a whole unit. We'll see.


  1. I love the blog. It motivates me that you have been spending so much time at the garage and also keeping up his great blog!
    "Garage Mate"