MKTR Posted January 3, 2023 Report Share Posted January 3, 2023 Hi All, I have started to install a 2 speed wiper motor into my TR4. I have wired everything up to a new 2 speed pull switch and all seems to work OK. My problem is that the Lucas pull switch BHA4578 does not go through the original switch plinth holes. As this was an upgrade option for the TR4 I wonder what I need to do the get the switch to fit where the single pull switch sat. Do I have to drill out the current plinth face? Is there a different pull switch? Maybe I will have to go to a toggle switch? Sorry But I cannot see any mention of this in the number of previous posts about wiring options. Many thanks Mark Quote Link to post Share on other sites
badhuis Posted January 3, 2023 Report Share Posted January 3, 2023 53 minutes ago, MKTR said: As this was an upgrade option for the TR4 Was it? Never heard of that before. Of course it can be done and has been done many times, but was it a factory option? Quote Link to post Share on other sites
RAHTR4 Posted January 3, 2023 Report Share Posted January 3, 2023 Mark, An original single speed wiper switch has a throat diameter of 9.5mm and the hole in the switch plinth has one flat side to stop the switch turning in use and keep the switch knob in its correct orientation.. The original two speed wiper switch was a Lucas Model 58SA part number 34477 as shown in the photo below and it does have a larger throat diameter (I do not have one to hand to measure) and a different chrome fixing bezel. Therefore the existing small hole in the switch plinth will have to be opened up to suit, but again you must leave a single flat to stop the switch rotating in use, plus it keeps the switch knob logo in the correct orientation I presume the number BHA4578 is for a reproduction two position switch so I really do not know what one looks like, so I have added a photo of an original two speed switch for you to compare. Also a Two speed wiper motor was an optional extra on a TR4 and became a standard fitment with the introduction of the Tr4A. Regards, Richard Quote Link to post Share on other sites
boxofbits Posted January 3, 2023 Report Share Posted January 3, 2023 Mark, you have a PM. Kevin Quote Link to post Share on other sites
RAHTR4 Posted January 4, 2023 Report Share Posted January 4, 2023 Mark, I have just checked an original 58SA switch and the throat size is 15mm in diameter.. Regards, Richard Quote Link to post Share on other sites
MKTR Posted January 4, 2023 Author Report Share Posted January 4, 2023 Thanks All, BHA4578 is the part number quoted by many suppliers for the Lucas 34477 58SA - apologies for the confusion. If the "two speed wiper motor was an optional extra on a TR4 and became a standard fitment with the introduction of the Tr4A" I wonder how TR4 owners managed the switch at the time? Maybe there is a solution out there that does not involve drilling out the plinth. Mark Quote Link to post Share on other sites
RogerH Posted January 4, 2023 Report Share Posted January 4, 2023 Hi Folks, the external dimensions of the BHA4578 is/are the same as the original 34477. However the build quality may not be as good. Although Ideal, a flat in the mounting hole is not essential for the BHA4578. It is held in place by a chromed nut that can be tightened quite effectively. As the knob is a Push/Pull design there is no serious turning involved. So the hole in the TR4 facia can easily be enlarged with a cone cut 'drill' Roger Quote Link to post Share on other sites
MKTR Posted January 4, 2023 Author Report Share Posted January 4, 2023 Hi, I wonder if I could use a pipe reducer to thread over the 15mm end and then push through the 9.5mm plinth fro the bezel/nut? Mark Quote Link to post Share on other sites
RogerH Posted January 4, 2023 Report Share Posted January 4, 2023 Noooooooooooooooooooooooooooooooooooooooooooooooooooo You will kill the switch Roger Quote Link to post Share on other sites
RAHTR4 Posted January 5, 2023 Report Share Posted January 5, 2023 Mark, As Roger has said modifying the 58SA switch is not an option as the part with threaded end is made of cast mazak so very brittle. In order to use the 58SA switch you will have to enlarge the hole in the three pieces that make up the switch plinth. This is what Triumph had to do in period as it is my understanding, all the optional extras were Factory fitted. Regards, Richard Quote Link to post Share on other sites
MKTR Posted January 5, 2023 Author Report Share Posted January 5, 2023 6 hours ago, RAHTR4 said: Mark, As Roger has said modifying the 58SA switch is not an option as the part with threaded end is made of cast mazak so very brittle. In order to use the 58SA switch you will have to enlarge the hole in the three pieces that make up the switch plinth. This is what Triumph had to do in period as it is my understanding, all the optional extras were Factory fitted. Regards, Richard Thanks Richard - that explains why Roger was so adamant about not doing that option. I will start the process of enlarging the 3 pieces - moulded plinth, steel strengthener, and 'chrome' finisher. At least I know which is the best way forward now and have a weekend job to do. Mark Quote Link to post Share on other sites
RAHTR4 Posted January 6, 2023 Report Share Posted January 6, 2023 Mark, Just couple of pointers - the holes in the aluminium finisher and plastic moulded plinth can both be completely round. The hole in the steel bracket is the the one which should have a single flat side. If the reproduction switch is similar to an original switch it will have the knob locking pin sticking out at 3 o'clock. An original two speed wiper switch knob has the locking pin hole at 6 o'clock so you will have to rotate the switch, to keep the wiper logo vertically up. Alternatively the logo can be taken out and turned, however the clear plastic lens can be very stubborn to remove without shattering and the small steel clip under the logo is often rusted. Have you found a larger chromed fixing bezel...? Regards, Richard Quote Link to post Share on other sites
MKTR Posted January 9, 2023 Author Report Share Posted January 9, 2023 On 1/6/2023 at 5:19 PM, RAHTR4 said: Mark, Just couple of pointers - the holes in the aluminium finisher and plastic moulded plinth can both be completely round. The hole in the steel bracket is the the one which should have a single flat side. If the reproduction switch is similar to an original switch it will have the knob locking pin sticking out at 3 o'clock. An original two speed wiper switch knob has the locking pin hole at 6 o'clock so you will have to rotate the switch, to keep the wiper logo vertically up. Alternatively the logo can be taken out and turned, however the clear plastic lens can be very stubborn to remove without shattering and the small steel clip under the logo is often rusted. Have you found a larger chromed fixing bezel...? Regards, Richard Thanks Richard, Holes now enlarged with a cone drill bit and the switch is in. I had the larger bezel from an old TR4A wiper switch so that is now fitted instead of the slimmer type that comes with the new switches. There is no room to turn the new switch 90 degrees as it then interferes with the ignition switch and washer pump, so the knob logo/symbol is at a jaunty angle. I have yet to attempt removing the plastic lens as there does not appear to be any wriggle room to get beside/under it. I may try drilling a now hole at 3 o'clock into a spare knob and see how that goes. Mark Quote Link to post Share on other sites
stuart Posted January 9, 2023 Report Share Posted January 9, 2023 (edited) 37 minutes ago, MKTR said: Thanks Richard, Holes now enlarged with a cone drill bit and the switch is in. I had the larger bezel from an old TR4A wiper switch so that is now fitted instead of the slimmer type that comes with the new switches. There is no room to turn the new switch 90 degrees as it then interferes with the ignition switch and washer pump, so the knob logo/symbol is at a jaunty angle. I have yet to attempt removing the plastic lens as there does not appear to be any wriggle room to get beside/under it. I may try drilling a now hole at 3 o'clock into a spare knob and see how that goes. Mark Make sure that there isnt one of the tags touching the metal dash as its easy to do with those larger switches. Stuart. Edited January 9, 2023 by stuart Quote Link to post Share on other sites
RAHTR4 Posted January 9, 2023 Report Share Posted January 9, 2023 Mark, It is interesting that you say the switch cannot be rotated by 90 degrees – this clarifies something I have wonder about for a long time, the TR4 light switch original part number was 34477 with the knob location pin at 3 o’clock whereas the TR4A two speed wiper switch had a part number of 35521 so the only logical reason for a different part number is that the knob location pin was re-positioned to 6 o’clock, however I have never seen a 35521 switch to confirm this. The re-positioning of the logo is not impossible, just be very careful, also all the parts must at room or above room temperature, not cold or the edges of the plastic lens can break off / shatter. The original knobs are built up as follows ; The knob itself has a shallow rebate inside its base and returns up each side, into this rebate fits a “U” spring steel clip which has “double claws” on each side upstand, the logo is a flat aluminium disc which has two projecting pips, these pips locate either side of one of the upstands dependent upon which way you wish it to point, the clear plastic lens is concave on each side and this is simply pressed down into the top of the knob and the double claws dig into the plastic which holds everything in place. In your case it seems to me that your spring clip will be running from 12 o’clock to 6 o’clock and thus not be sitting in the existing rebate, I have not had any problems with this before, it is just a matter of getting the plastic lens to engage with the double claws by pressing everything together. Another thing is to check is the condition of the steel spring clip as unfortunately they can rust rather badly...! Hopefully the photos below of the parts will provide some clarification. Regards, Richard Quote Link to post Share on other sites
Lebro Posted January 9, 2023 Report Share Posted January 9, 2023 Easier to drill a new hole at 90° I would have thought Bob Quote Link to post Share on other sites
RogerH Posted January 9, 2023 Report Share Posted January 9, 2023 (edited) Hi Bob, the hex hole in the knob is not uniform. The flat for the spring blip is distended. Simply making a new hole for this blip will not allow it to fit in the hex hole. Roger Edited January 10, 2023 by RogerH Quote Link to post Share on other sites
RMP NC Posted January 9, 2023 Report Share Posted January 9, 2023 I put the Lucas 3-Way switch in for my wiper too but I made the 3rd position an electric washer. So, all the way in is off, one click out is the wiper (one speed) and next click out is wiper and washer. I experienced the same issue with hole size and the drill came out. BTW, I also put the same Lucas 3-way switch in the hole where previously the Washer pump went and I use that to turn on and select between two electric fuel pumps. I am even making a fuel label to go in the knob. Absolutely having to put a new catch hole in the new Wiper knob because the switch has to be rotated and will NOT fit where the catch button faces down. Quote Link to post Share on other sites
MKTR Posted January 10, 2023 Author Report Share Posted January 10, 2023 Thanks for the continuing advice, especially the point from Roger about the Hex hole and the images from Richard. I had a go at getting the lens and logo out and I was surprised how easy it was once I could get a lever beside the clip - so easy that the metal clip flew across the room. The main issue now is that the clip has to remain in its original position due the the rebate but I need to rotate the metal disc, which has ears to go either side of the clip. I will see if any of my spare knobs could be used to take the wiper logo/disc but otherwisie I think that I will have to lose the ears and fix the disc to the knob with an adhesive or add some form of spacer underneath. I presume that the lens will not have enough pressure to stop things moving. Mark Quote Link to post Share on other sites
RAHTR4 Posted January 10, 2023 Report Share Posted January 10, 2023 Mark, I have assembled knobs with the steel clip laying outside the rebate, it make the three parts slightly thicker, however pressing everything together all was firmly clipped in place. Your other option is the remove the two projecting pips on the logo so it can be rotated in the desired direction – not sure if this would need gluing as I have never done it. Regards, Richard Quote Link to post Share on other sites
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