Damaged Stub axle repair

As mentioned previously I damaged the threads of the off side stub axle extracting it from the suspension upright, this is how I repaired it. To do this, you need at your disposal a vernier caliper, the Japanese digital ones by Mitutoyo are the best available, you will also need a thread chaser, a die wrench, a a good quality carbide cutting tool, and a decent Lathe. The Lathe I repaired this on is an old 1970's Colchester Triumph 2000, a fantastic well built lathe.

I started by locking the stub axle into the three jaw, and making sure its  centred, you can clock it if you think it’s totally necessary, but I know this three jaw chuck is pretty centre so I didn’t bother.

I then proceeded to cut a small taper into the end of the stub axle  using the cross slide with a carbide cutting tool cutting no more than 5 thou deep, just to take the threads of the damaged end, turning at around 425 with plenty of water soluble suds.

I then ran a thread chaser, 24 TPI UNF through the remaining threads just to increase the definition of the remaining threads on the end of the axle to help with the next step.

 

Pinning a die wrench with a ½ 24 TPI UNF die between the tailstock the and job with the wrench handle jammed against the bed, I slowly proceeded to turn the tail stock leaver and the headstock simultaneously  by slowly by hand keeping the die straight until it bites onto the first thread and begins to cut. This ensures an clean straight cut thread perfectly incline with the old one.

It worked and a cleaned the thread up and threaded a new nut on just to make sure it was nice and tight, Good as new! Danaged stub axle repaired.

Front Suspension rebuild Part 1 - Break Down

Work has begun and has been pretty much completed on the rebuild of the front suspension of the Scimitar. The front suspension like most of the scimitar is totally shot and most of it has had to be replaced. Both the top ball joints are crap, and the boots are split and spilling grease all over the place, the bottom trunnions are crap with perished grease seals, not one suspension bush has stood the test of time, all falling to pieces and it just looks generally crap.

First thing is to strip the off side and near side units into individual pieces and box them up. So not to mix up the different sides, I marked each of the off side parts with red paint and each of the near side with blue paint. The majority of the parts are interchangeable, but after nearly forty years working together its best not to mix up to sets of suspension components as these things tend to wear in together and work better as a set after a while and mixing this up can mess up that aged harmony.

Some imagination was required to remove  some of the 40 year old bushes and the nylon bearings in the bottom arms, alot of the grinder, drill and fly press.

 

 

Stripping this suspension down proved to be a total pain as some of it hadn't been apart in over 30 years. The 1000 lb impact gun and the hack worked over time that day. Which isn’t a problem, as am replacing all the nuts bolts and washers as a go along, and where I can replacing everything with a standard metric equivalent for two reasons, ease a assembly and dis-assembly and cost, metric bolts are usually much cheaper these days than the UNF found in the Scimitar. The majority of the bolts am using are high grade stainless steel, and usually Allan head cap bolts, purely because they look better. All bolts am using are a minimum of 8.8 grade GB5782, just so I know there not going to rust away and snap. More than half of those nasty rubber bushes had to be drilled to bits and burned off with the oxy-acetylene, just because they were so tight and stubborn. 

 Lucky I’ve got some nice new Polyurethane bushes to replace them stacked up an ready to be fitted :)

The only problem is I’ve damaged the stub axle thread on the off side knocking it out the upright. Being a thirty year old tapper it proved a bit tight and required a big hit to get it out of the carrier, and a school boy error on my part. Always hit the top of a nut, not an open thread, as although these stub axles are hardened machined steel, the thread ends have been exposed to the elements for a long time and the oxygen has softened them up a bit. it could have been worse, just a few mashed up threads a bit hard work and a good Colchester lathe and ill have it sorted.