Wiper sweep area

[barry153]

Hello, my 1968 TR5 has never had the correct sweep since I bought it in 1999.

If I set it on the splines so that it starts from lowest edge of the screen on the drivers side it then only travels to just past the vertical so the passenger side hardly gets wiped at all.

On querying this with a Triumph repairers I was told it should have a 120 degree gear wheel in the wiper motor but when I had a look my car had indeed got a 120 degree wheel!

Where do I go from here?

All suggestions welcome.

Barry.

[peejay4A]

Condition of the wheelboxes is the next thing to look at.

[RogerH]

Hi Barry,

if you are sure that the motor has the correct gear wheel then as Pete suggests have a look at the 'wheel boxes'

 

The TR5 should have P/no 37H6316 same as the late 3 - 4A

The TR6 has the 37H7738

 

I don;t know if there is a difference but worth a check.

 

Also look for slack in any of the joints/connections

 

Roger

Edited August 29, 2017 by RogerH

[AlanT]

If you are absolutely sure that its a 120 gear and they are clearly stamped, then you must have the wrong wheel-boxes.

 

You could fit a 130, 140 or even a 150 gear in the motor. This is a bodge and will eventually puzzle someone else.

But fitting wheel-boxes is a pain.

 

I rebuild wiper-motors and will swap a gear with you.

 

Oh, I just had an idea. From time to time crank-pins break off from the drive-plate. Mechanics have been known to braze them back. It's impossible to do this accurately without a jig.

 

I've seen a few like this, so do check. For a 120 sweep the axis of the crank-pin should be 12.4mm from the centre of the drive-plate. Every mm error gives a 10-degree change in sweep.

Edited August 7, 2017 by AlanT

[barry153]

Hello All,

Many thanks for your replies. I have been away so sorry for the delay in answering.

I have heard that wheel boxes are a pain and probably beyond my limited ability!

I think I may follow Alan T's suggestion and look at the drive plate.

Thanks again,

barry153.

[JRCWeedon]

Hello All,

Many thanks for your replies. I have been away so sorry for the delay in answering.

I have heard that wheel boxes are a pain and probably beyond my limited ability!

I think I may follow Alan T's suggestion and look at the drive plate.

Thanks again,

barry153.

I had exactly these symptoms on a newly rebuilt TR4 I checked everything even replaced the rack (the wheelboxes were fine thank goodness) it eventually came down to a worn out gear wheel even though it was the right degree.

Alan might be able to supply one otherwise it is the dreaded ebay

Regards

John

[BlueTR3A-5EKT]

Hi Barry,

if you are sure that the motor has the correct gear wheel then as Pete suggests have a look at the 'wheel boxes'

 

The TR5 should have P/no 37H6316 same as the late 3 - 4A

The TR6 has the 37H7738

 

I don;t know if there is a difference but worth a check.

 

Also look for slack in any of the joints/connections

 

Roger

The 37H6316 wheel box has a smaller diameter drive gear than the 37H7738 from a TR6. ( I think it is 28 teeth compared to 32) This means for the same given rack axial movement the wheel box rotates a different arc.

Peter W

[AlanT]

120 gears are hard to get. I now rely on moving the crank-pins on 150 gears, which are plentiful. Will be making another batch sometime soon.

[peejay4A]

...and some 115s Alan?

[AlanT]

Yes I'll make a few 115's. Been useful inn several cases.