robin craig Posted November 12, 2017 Share Posted November 12, 2017 Recently we were getting ready for a parade and doing checks on a diesel Scimitar. When started the vehicle sounded as if it had a handful of bolts rolling around inside a concrete mixer so it was shut down and the hunt was on for a cause. A bearing failure was suspected. Upon opening gearbox deck and pulling up the radiator the belt was found to have walked on the generator or alternator pulley. We suspected that the bearings were gone in it but as we went no further and VOR'D the wagon for the parade I am wonder a few things. First off has anyone replaced the bearings in one of these generators themselves and if so is there a thread here for that? Is it possible that the fan bearing has gone and caused the belt to walk over? It is a job for winter maintenance to get at, just trying to get prepared. Quote Link to comment Share on other sites More sharing options...
sirhc Posted November 12, 2017 Share Posted November 12, 2017 Robin, I would say the noise is likely to be the fan rather than alternator. You need to take the belts off and give everything a wiggle. Jumped belt could be the tensioners are loose or bearings gone in those? Chris Quote Link to comment Share on other sites More sharing options...
terryb Posted November 12, 2017 Share Posted November 12, 2017 common problem Robin, two small bearings in the tensioner wheel fail, causing the tensioner wheel to run at an angle, and the belt is then 'led off' replaced mine with quality bearings and hasn't re-occured (yet...) Quote Link to comment Share on other sites More sharing options...
robin craig Posted November 13, 2017 Author Share Posted November 13, 2017 Thank you to you both. It isn't my vehicle and honestly it was an instant decision of "it isn't going on the road" and that was as far as we went, dropped the deck and moved on to the next wagon. I will report to Al the comments and see what he wants done. Cheers Quote Link to comment Share on other sites More sharing options...
Andrew Rowe Posted November 13, 2017 Share Posted November 13, 2017 Just for the record, the Main Fan pulley bearings are, LJ30 WRR, which is 30mm x 62mm x 23.8mm and the other one is 207 KTT , which is 35mm x 72mm x 25mm. I have the belt tensioner number some where, will see if I can find it. I replaced mine and skimmed the pulley also. But I have noticed a little while later that it has a slight wobble, so must have been a cheap bearing? Cheers Andrew. Quote Link to comment Share on other sites More sharing options...
sexton Posted December 2, 2017 Share Posted December 2, 2017 I just repaired this vehicle. Problem was a bad fan bearing, the larger one that supports the drive belt loads. The bearing cage had broken up so the balls were all piled up against each other, so good call on not using the vehicle, Robin. Spinning the alternator and its tensioner and listening with a stethoscope when running after repair showed the alternator and tensioner bearings were in good shape but we'll be keeping an eye on the belt. I suspect the fan moving axially caused the belt misalignment, as suggested above. Andrew, that's interesting info about the fan bearings! When I saw those unusually wide bearings in the parts manual, I thought, "that's can't be right!" They are so much wider than stock 62 series bearings. But your info shows they are (or were?) available. Then I realized that the spacers I found inboard of each bearing, which are not shown in the parts manual, had been installed to allow use of stock 6206 and 6207 bearings. So were the original bearings heavier bearings? The larger 6207 does look a bit light to take the loading of two belts. Anyway, she's up and running again (once I fix the leaking steering master cylinder). Talking of that, you leave these CVRTs out in the rain and they accumulate 2" of water on the floor which submerges the steering and main brake m/c's. That isn't good. So they have no floor drains? And no interconnection between sections divided up by cross members so one drain would suffice for all? Drilling five 3/8" holes through ~1 1/4" thick aluminum to drain all the areas accessible from the driver's compartment took me about an hour or so and two or three drill bits. Malcolm Quote Link to comment Share on other sites More sharing options...
robin craig Posted December 2, 2017 Author Share Posted December 2, 2017 Malcolm, glad to hear you now have it fixed, it was quite the noise wasn't it? There is a floor drain and it is operated from the drivers position. Do not forget that originally these vehicles were designed to float, keeping water out was a design concern. I should perhaps speak to you privately about a couple of other issues I noticed which I reported on a couple of other vehicles that weekend. Robin Quote Link to comment Share on other sites More sharing options...
andym Posted December 2, 2017 Share Posted December 2, 2017 A friend of mine with a diesel Sultan has taken a drill to his for the same reason. A better engineering solution would be to drill and tap UNC for some blanking plugs. Andy Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted December 2, 2017 Share Posted December 2, 2017 6 hours ago, robin craig said: There is a floor drain and it is operated from the drivers position. Do not forget that originally these vehicles were designed to float, keeping water out was a design concern. Robin the foot operated dump valve only drains the transmission compartment. The water contamination of the steering and brake master cylinders was an issue when in service over 25 years ago. When one of the guys at our Workshop sent in a staff suggestion to MoD at the time to fit a drain plug, the reply was No, it would weaken the floor if a mine or similar went off under it. I would say for a private owner fit a drain plug. If you left it as an open hole water would be force in if driving through it. Richard Quote Link to comment Share on other sites More sharing options...
robin craig Posted December 2, 2017 Author Share Posted December 2, 2017 (edited) Richard, I was aware of the fact that only one portion of the hull was drained, but I appreciate you clarifying that, sometimes we expect everyone to know everything, I think that is what i did. I know that some of the CVR(T)s that I have worked with over here have had holes drilled in them, allegedly by Withams as a simple method of draining them. I think it is a fairly common misconception by newcomers into the hobby that like a family car when you shut the hatches it is watertight. I constantly see or hear of CVR(T) and FV432 and Ferrets that have filled up with large quantities of water very quickly and stunned owners wondering why. While on the subject, running without inspection covers underneath is also so common, with obvious results. . Edited December 2, 2017 by robin craig Quote Link to comment Share on other sites More sharing options...
sirhc Posted December 2, 2017 Share Posted December 2, 2017 Robin, Withams would not have bothered drilling holes in them, I have been in and bought many vehicles from there which were full of water, including Al's Scimitar which had water about 12" deep in it when I first saw it! Most owners have drilled holes in them when restoring them, I have done it to most of the ones we've had. The petrol Spartan came from the MoD with some holes already drilled in it. Glad the horrible noise was just the fan bearing. At least it didn't fall to bits while out on the road like mine did once! Chris Quote Link to comment Share on other sites More sharing options...
sexton Posted December 2, 2017 Share Posted December 2, 2017 To those of you considering drilling drain holes, I must pass on something I learned today. Using a couple of new TiN-coated bits, it took me 15, 20 mins to drill one hole in the floor, with a lot of pressure on the drill to keep the tip cutting. I decided to try another drill set I have. It took me 2 mins. The bit went through the floor like a knife throughout butter. The difference in bits was the rake angle behind the cutting edge. The good bit had a steeper rake. So if it takes more than a couple of minutes to drill each hole, get a better bit! Malcolm Quote Link to comment Share on other sites More sharing options...
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