Orgasmic Farmer Posted December 23, 2011 Share Posted December 23, 2011 I have a very early 110 I am currently rebuilding. I had heard of an interesting modification to improve the wipers which involved fitting shortened Discovery arms to the wiper spindles to take advantage of the stronger springs on the longer arms. However there was little info out there so I thought I would do a little write up in case anyone else is interested. My first problem is that the wheel boxes on the early 110 are the old type that take the push fit floppy wipers. So first up it was necessary to fit the later wheel boxes with the M8 nut and taper fitting which will accept the discovery wiper arm. These boxes are fitted to later TD5 defenders and have part number DKU500010. However, these later spindle boxes have a bigger oval spindle. I had to drill the bulkhead out to 13mm and then enlarge the holes sideways with a dremel to get the spindles to fit. The TD5 bulkhead has a wider channel at the mounting points put they do (just) fit OK on the older type if care is taken. The gear is also larger than the early type and has 40 teeth as opposed to 32 and as such takes up a bit more space. Resized to 88% (was 800 x 600) - Click image to enlarge Refitting the drive cable highlighted the next problem with the larger gears meaning it now runs about 1cm higher up the bulkhead. So the central stiffener needed modifying and the cable bending a little bit to get around this. Resized to 88% (was 800 x 600) - Click image to enlarge The brighter ones out there will also realise that the extra 8 teeth on the gear will alter the distance the flex drive is able to push/pull the gears and in turn lead to a reduced swept area. To get around this I fitted the gear and crank from a late TD5 motor (available cheaply enough as a genuine part PN. DLW000020) at the other end of the sytem. This has the crank mounted more outboard on the driven gear which leads to a greater stroke on the flexidrive thus restoring the original stroke to the wipers. The early type crank is marked 113 degrees and the later one as 150 IIRC. Unfortunately I have no photos of this but it is a very straightforward swap involving a circlip and 4 screws on the motor housing! Next up was to modify some discovery Tdi wiper arms to fit the new spindles as this was one of the main reasons for the upgrade. The disco arms, being larger and longer, have stronger springs than the defender ones so theoretically when cut down should be even better (though I have yet to test them). Here are 110 and disco units side by side Resized to 88% (was 800 x 600) - Click image to enlarge First up, remove the springs from the arms. Pull one off and the other falls off. Resized to 88% (was 800 x 600) - Click image to enlarge Then cut clean though the arm leaving the right length on the bottom bit for later. Resized to 88% (was 800 x 600) - Click image to enlarge Now you have to separate the inner and outer bits from both sections of wiper. On the top bit I cut it through again to leave only the length of inner needed when reassembled since that means there is less centre to drift out. They are a very very tight fit and I was unable to simply tap the middle bit out so I used a slitting disc and carefully cut the outer off. On the lower part of the arm you need to first remove the rivet. Unfurtunately this seems to be made of the hardest metal known to man! I used a small disc to grind it down flush with the spring mounting plate which I then levered off and then ground it down again level with the inner part of the arm. It would still not drift out so at this stage I ran a thin disc up the full length of the central bit careful not to damage the outer part. With a slit in the rivet it was possible to knock it out and then fairly easy to drift out the central section Resized to 88% (was 800 x 600) - Click image to enlarge The shortened end piece can then be knocked back into lower section to the correct depth. Check length with the original 110 item. When happy I drilled through the old rivet hole, through the shortened arm and through the spring mount. I then tapped them for an M5 screwhead bolt (just to minimise and chance of movement) and then bolted it together. Resized to 88% (was 800 x 600) - Click image to enlarge A bit of tidying and a coat of paint to finish (not done yet) and here are the 2 new wiper arms ready to fit the TD5 spindles and the old one as comparison Resized to 88% (was 800 x 600) - Click image to enlarge It will be a while before I get to test this modification so cannot say if it was worth the effort yet! But if anyone else want to try it is not especially hard, particularly if your bulkhead is in bits as mine is or if you already have the later type spindle fitted. Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted December 23, 2011 Share Posted December 23, 2011 Interesting, look forward to seeing how it works. Only problem I can forsee is the motor's ability to pull the blades with the extra friction? Especially if the screen is not very wet. I guess this issue would be reduced on the later (post 2002) Td5 models, from which your later wheelboxes and gears originate, that have the different motor position (which reduces cable friction by removing the bend). In either case, ensuring the motor is well greased will help it no-end. Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted December 23, 2011 Author Share Posted December 23, 2011 got me thinking just how much stronger the springs are. So back down the shed with a kitchen scales (don't own a spring balance!). Old, & well worn 110 arm puts 250 grams of pressure (OK not correct unit of measurement I know) when held in working position. The shortened Disco arms put in 600 grams. Given my oild arms are about worn out I reckon it is probably twice as much push as a new arm would have. Probably some high silicon wiper blades will compensate to some extent for the extra friction that will be generated. Interested if anyone else has heard of?tried this mod already? If it doesn't work out I will just get later TD5 defender arms. Quote Link to comment Share on other sites More sharing options...
GBMUD Posted December 23, 2011 Share Posted December 23, 2011 Could you not just have fitted the twin springs from the Disco arms onto the original 110 arms? I know that would not have made such an interesting thread... Chris Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted December 23, 2011 Author Share Posted December 23, 2011 Oh that it was that simple Chris. Unfortunately not! Quote Link to comment Share on other sites More sharing options...
mickeyw Posted December 24, 2011 Share Posted December 24, 2011 An interesting mod Mark and well illustrated. I'm sure I've heard of this mod once before but without this level of detail. I guess you already looked at later arms to see that they didn't already have stronger springs James - I can't imagine the extra cable length and associated friction would make too much difference. I haven't looked at a Td5 motor, but how different is it really ooommph wise? ( I appreciate the location differences) Will wait to hear how worthwhile it is Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted December 24, 2011 Share Posted December 24, 2011 I'm not sure if there's any difference in motor strength through windings etc., I'll have a look when I come to do the bulkhead on the 110. The reason for the re-positioning was to improve wiper performance, presumably they felt that the friction from that bend in the guide tube was enough of a drag to be worth removing. I'd agree that it wouldn't make much difference though, and I'd go as far to say that a well-greased early setup would be far better than an abused later one. Quote Link to comment Share on other sites More sharing options...
Victor Normandy Posted August 13, 2020 Share Posted August 13, 2020 I know i'm digging up an old thread here, but do you have front pictures of the enlarged "oval" hole you made on the bulkhead ? As on the pre 2002 bulkheads the factory "round" holes sit very close to the edge of the bulkhead vents, did you start to drill the hole off centered so it sits higher ? Quote Link to comment Share on other sites More sharing options...
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