Whitlock Cobra - repairs and maintenance

[gilesfordcrush]

Hello all,

I have searched the forums, and can't specific find an answer to this.

I have a Whitlock Cobra steering system fitted to my 1978 Moody 30. I was unhappy that I could not remove the top cover from the pedestal, the four bolts were seized. After several evenings of hard work I have removed the broken and snapped studs from the aluminium casting. My next job is to clean up the threads of two of the holes, as they are a little damaged. If this fails I will need to oversize the holes a little and re-tap.

I'm hoping to be able to run the tap down the holes and get the threads clean enough to accept the new bolts. Is tapping aluminium different to steel?

I did not have any problems with the steering, but I'd like to inspect it, clean out the old grease etc. Can anyone advise what type of grease I should use? It is a rack and pinion type mechanism. I can't find any documentation regarding how to take it apart, or in what order, can anyone advise?





Many thanks,

Giles

 

[Kukri]

I'd drop a line to Cliff Mogridge:

http://www.winchservicing.com/

Very helpful chap and the complete Whitlock expert.

 

[captainboo]

Just use the tap as you would in steel with a bit of grease on it to catch any swarf and lift it out the hole. It is a lot softer than steel so be careful that you have really 'caught' the existing thread and are not cutting a new one. If you cannot repair the thread then I would use a 'Helicoil' kit to repair it.

Grease wise I just use a good quality car type grease designed for general purpose automotive use - nothing special is particularly required.

Unfortunately you cannot disassemble the pedestal any further without removing it from the boat and grinding off the weld that holds the output arm onto the vertical shaft. Sounds daft but that is what the instructions say! You can undo the four bolts that hold the input pinion/wheel shaft housing in place but it should be shimmed properly on refitting and if you have no problems with it such as backlash/worn bearings then I would just clean out the old grease and put new stuff in and leave it alone.

Use Dualac on the bolts that hold the top cover on and ensure that the foam gasket under the cover is ok so that it keeps water out so that the bearings don't corrode.

 

[gilesfordcrush]

Hello Captain Boo,

Thank you for the very informative post, much appreciated. I have not used the Helicoils before, but hopefully the tapping will go well. I am pleased you have warned me about further dissasembly, thank you! A potential disaster avoided!

My Duralac tube is standing by - although there was no gasket in place - I will make up a cardboard one myself, or get creative with the butyl tape perhaps!

 

[Cardinal]

I have used silicone sealant to seal the top cover which seems adequate since it is simply a cover.

 

[gilesfordcrush]

I retapped the four holes in the pedestal last night, and all was going very well, until the very last turn of the last hole, and the tap snapped off! The lower half of the hole now has the tap deeply embedded within it! Perhaps I'll buy a tap extractor set and see if I can get it out........

 

[Cardinal]

If that doesn’t work, you could shorten the stud which only has to hold down the cover.

 

[gilesfordcrush]

I did just that, and shortened the bolt. I would rather make a proper job of it, but am a little reluctant to buy a broken tap extractor. I only use the tap and die set once a decade!