Thread: underbody overhaul

ON to the front axle now...started to de-greased it this morning...this photo gives you an idea of the state of things underneath - nothing more serious than surface rust, but high time to sort it out.
Once it is de-greased, rust converted and painted, on will go a new set of suspension bushes and 3 degree QT cranked radius arms.

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Disapointed today to find that the POR-15 paint has failed on the cast metal of the rear dif. I followed the instructions meticulously, degrease with marine clean, wash and allow to dry, then coat with metal prep, then wash again and allow to dry, then two coats of POR-15.

In many sections of the diff the paint just peels off with bit of a scratch with a spatula- no trouble, it would not stand up against repeted stones, mud etc....very unhappy about this. It is supposed to bond and cure within 96 hours..it has been on for almost a month now.

It has also failed in 1 or two very small places on the seams of the rear axle, but not as bad as the almost complete failure on the cast metal.

Anyone considering using POR-15, at this point I would advise against using it on cast metal components...I would be reluctant to recommend anyone use it at all now though...unitl I re coat and see what happens.

I will be following this por-15 coating with Dynax UB, an underbody wax - in hindsight its possible that just using a normal enamal underbody paint, followed by Dynax UB, would have been fine.

Anyway, I will re-treat the sections that failed first time aroud and report back in a few weeks.

I only ever high pressure wash the underneath then underbody wax the the lot, I also use old sump oil in the cavities under there, mainly the chassis rails and sills, not a sign of rust despite alot of beach driving and heaps of rock mud offroad, I have had excellent results with POR15 on a classic car I restored and used almost daily but not on cast metal.

HI Ade,

Yes, I am just going to remove all the por 15 paint off the cast section of the diff housing and just re-test a small section before I re coat the whole thing with por 15 again.

If the test section fails a second time, it will just get Dynax UB under body wax.

In hindsight I probably could have got away with a good clean, a rust converter and just the dynax under body wax.... the POr 15 had definitely made this a longer ( much, much longer) job.

Started cleaning the long range tanks today. Started out looking like this;



Ended up looking like this;




Tomorrow is metal ready/ rust conversion and then Monday is the first coat of POR-15.

Well, after cleaning and rust prepping the long range tanks, I then painted all the bare metal bits with 2 coats of Por-15, waited a week and today put on the coat of primer over the whole lot.
Next up, two coats of Por-15, followed by two coats of Dynax. Hopefully by then, my new radius arms have turned up from the UK,one of these days I will get the disco back on the road.

Your far too patient this is mud time. It's time to get her dirty. Put her back together take her for a run up to a nice muddy track and sink the boot in. Your missing out on the fun season