Revitalised Wiper Delay

#1
Finally got around to sorting out the windscreen wiper delay, which has never worked since I purchased the car :( I decided that I would completely strip down the wiper motor, delay governor and wheel boxes, clean everything, re-lubricate, re-assemble and pray :shock: :shock: :shock:

Before starting, as usual for an electric job, I disconnected the battery :D


Before starting


First the wiper arms are removed


The retaining nuts, washers and cover washers are removed from the wiper boxes


The two screws and nuts from the air intake valance are removed...


...as are the two drive screws at the outer ends of the valance


And there it was...gone


Pull off the vacuum pipe from the governor, followed by the wires


Unscrew the hex nut securing the drive cable tubing


Disconnect the earth from the motor casing


After removing the three mounting nuts and washers, pull the motor and cable from the tubing

So now the motor is out :p


First part of the strip down was the removal of the delay governor from the motor body


followed by the unscrewing of the remaining 3 cover screws and removal of the cover


Removing the spring clip and washer...


...allows the connecting rod and washers to be withdrawn


The cross head can now also be removed


Removal of the final gearshaft spring clip and washer from the underside...


...allows the gearshaft to be removed.


The dished washer can now be removed. According to the Workshop Manual, mine was fitted the wrong way around :shock:


The thrust screw and locknut are next to be removed


Unscrew the long through bolts holding the armature cover...


...and pull slowly until the three brushes have cleared the commutator


The armature fully removed from the cover. Be careful not to lose any felt washers


Undo the two screws holding the limit switch (self parking)...


...and the three screws securing the brush assembly. Both items may now be removed with the wires holding them together


Strip down of the delay governor. Simply remove the four clips carefully, since the two halves are under spring tension, then remove the spring and diaphragm.


The five contacts of the limit switch assembly were cleaned up and sprayed with contact cleaner...


...as were the three contacts of the delay governor

Everything was then thoroughly cleaned. Have plenty of rag handy as there is a lot of grease to remove!!!


Now to get all of this back together :? :? :?


The brush assembly was first to be screwed back in place...


...then the limit switch


The freshly painted armature cover...


...motor bracket...


...and governor bracket


As with other owners on here, the three mounting rubbers had perished, so new ones were made from some pipe, bolts, washers and nuts (Nice idea Mike :D )


The newly cleaned governor attached to its newly painted bracket


The cover bearing was lubricated, as was the felt washer...


...and the armature replaced in the cover


Make sure that the cover marks line up, or the motor will run in reverse. Screw the cover on with the long through bolts


Having fitted and adjusted the thrust screw and lock-nut, I plugged the motor into the car, and tested that the two speeds worked correctly:- which they did :D


The final gear bushes were lubricated, the dished washer replaced, (the right way around), and the final gear placed in the motor body...


...and kept in place with the washer and spring clip


Grease was packed around the worm gear, final gear and cross head channel


The cross head was placed in its channel, the final gear crank-pin was lubricated, the connecting rod washer fitted, the connecting rod lubricated with grease and also fitted...


...and all held in place with the washer and spring clip


The cover was then replaced, followed by the delay governor actuator, and then finally the delay governor was screwed in place.

PHEW :shock:

I then removed the wiper wheel boxes from the car. Unfortunately, with the offside one, the nut would not budge, but the whole assembly still managed to slide out of the slot.


The assembly as removed from the car


The disassembled wheel boxes and drive cable tubing


A short while later, and all was much cleaner. Notice that I was still unable to remove the nut from the offside wheel box assembly, so it will have to go back on the way it came off :shock:


Wheel boxes both freshly greased up


All was then re-assembled, and fitted back onto the car. Fortunately the offside box is still a nice tight fit


The drive cable was then given a nice coat of grease...


...and the whole motor unit fitted back onto the car


All bolted in, wired back up, vacuum pipe re-connected, and ready to test.

The battery was re-connected and the wiper tested for slow speed, fast speed, and the missing delay:- which was now present. Success!!!

And there's more :shock:

Part of my preparation for the job, was to have a look at the circuit diagram to see where the most likely suspect would be for the missing wiper delay, (which was the governor switch by the way), and in doing so worked out how the four states, (off, slow speed, fast speed and delay) actually work, so I thought I might share them here for anyone else who is interested :? or has nothing better to do :shock:

In all of the following drawings, taken from the Workshop Manual, I have added red lines to show where the +12V power is routed to for each scenario. It also shows which terminals on the wiper switch are connected together for each scenario.

The key to the numbers is:

78 - Wiper switch
79 - Delay govenor switch
80 - Wiper motor, which incorporates the parking switch
82 - +12V feed fuse

The numbers on the motor assembly are:

1 - Ground
2 - Parking switch common connection
3 - Fast speed motor winding
4 - Parking switch NO (Normally Open) connection
5 - Slow speed motor winding

The cable colours are:

PLG - Purple/Light Green
ULG - Blue/Light Green
NP - Brown/Purple
NLG - Brown/Light Green
YLG - Yellow/Light Green
RLG - Red/Light Green
B - Black

Parking and Governor Switch States

The parking switch state changes as soon as the wipers start a sweep, and changes back as soon as the wipers return to the parked position. When the parking switch is in the off position, and the wipers have either been switched off or is awaiting the delay to end, the wiper motor will have an earth connection placed on both sides of the winding. This is to help collapse the magnetic field and prevent the wipers from 'running on'.

The delay governor switch changes state when the wipers are roughly halfway across the screen, and changes back when the delay time has been reached.

Wipers Off


In drawing 1, the wipers are in the parked position, and the +12V battery feed has nowhere to go so nothing moves.

Drawing 2 however, depicts the state of the switches when the wipers were in operation, but have now been switched off. The power is routed through the parking switch, (which changed state at the start of a sweep), and is routed through the wiper switch connections 6 and 4 to the slow speed motor. Once the wipers reach the parked position, the parking switch will change state again, thus removing the power from the motor, and leaving us in the same state as drawing 1.

Slow Speed


Drawing 3 shows the slow speed wiper selected. In slow speed the power is simply routed through to the slow speed motor winding, via connection 3 and 4 of the wiper switch.

Fast Speed


Drawing 4 shows the fast speed wiper selected. In Fast speed the power is simply routed through to the fast speed motor winding, via connection 3 and 2 of the wiper switch.

Delayed Wipers


This gets a little bit more complicated. Drawing 5 shows the state when delayed operation has just been selected, before the wipers have moved. The power is routed through the wiper switch via connections 3 and 5, then through the delay governor switch via connections 3 and 1, and on to the slow speed motor winding.

After the wipers move off, the parking switch changes state, followed closely by the governor switch. Drawing 6 shows this state, after both switches have changed.

If you follow the power from the fuse, you will see that the parking switch changing state has now provided power to the third connection of the governor switch, (connection 2), via the wiper switch connections 6 and 1. This means that when the governor switch changed state there was no loss of power to the motor.

When the wipers have finished their sweep, the parking switch will, as usual, change state again, thereby removing the power for the motor so the wipers stop. Drawing 7 shows this state. When the delay runs out, the governor switch changes state once again, leaving the switches in the same state as drawing 5, where the whole process will start over.

Simples :? :? :?

The above has been worked out for my vehicle, a 1972 3500S, and because I don't have the diagrams for other cars, there may be some variation, so check your own diagrams when fault finding. Hope this may prove helpful to someone :D
 

Mikep

Active Member
#3
Great post Phil, very detailed :D

Its a satisfying job to do especially when the wipers are nice and smooth and the delay works!

codekiddie said:
As with other owners on here, the three mounting rubbers had perished, so new ones were made from some pipe, bolts, washers and nuts (Nice idea Mike :D )
I'm glad I could offer a solution :D
 
#5
rockdemon said:
fantastic post! Nice job... stickied!
Thanks Rich :p

Mikep said:
codekiddie said:
As with other owners on here, the three mounting rubbers had perished, so new ones were made from some pipe, bolts, washers and nuts (Nice idea Mike :D )
I'm glad I could offer a solution :D
So was I Mike :shock: They worked a treat.

You will see that when I was part way through the rebuild, I tested the motor just to make sure all was OK, and the whole assembly would jolt with the force of the start/stop motion of the motor, so the rubber mountings are a must to lessen the impact when in situ. I was actually down to just one original mounting rubber being intact, and that was close to being terminal :shock:

billoddie said:
Excellent post. :)
Thanks, I hope it helps others out :D

I have now finished putting the air intake valance back on, and the wiper arms, and it all works great. Another job off the list :D
 

GRTV8

Well-Known Member
#9
Fantastic thread
You are a legend now . Whats next on your agenda ?
You are on the way to making the best workshop manual ever . I love coloured pictures with words
Gerald
 
#11
The Rovering Member said:
Bruiser's wipers are a little lazy after the break from the road. This would be a worthwhile job. Nice one!
Definitely worthwhile, and worthwhile doing it before the wipers need to be in more regular use :shock: which is one reason I did it now rather than later.

Johnny E said:
One of the best and most thoroughly written threads ever, with really useful photos. Great stuff
Thanks:- hope it helps.

Quagmire said:
Excellent post, many thanks for taking the time to document everything, outstanding!I need to do this on mine :shock:
Fortunately a fairly straightforward job, just a little bit messy with all the grease around :(

GRTV8 said:
Fantastic thread
You are a legend now . Whats next on your agenda ?
You are on the way to making the best workshop manual ever . I love coloured pictures with words
Legend??? Now you're just embarrassing me. There are plenty of others on this forum who, IMHO, have and deserve legendary status, but I don't count myself as one of them, and I will be sure not to use any black and white photos since you like the coloured ones so much :p

smokin1942 said:
Terrific report - 53 pics and 7 diagrams; now that's a job done properly!!
Think yourself lucky, 112 pictures in all were taken, I just spared you from them all :shock: iPhones are so useful for capturing step-by-step procedures like this :p
 
#13
Wasn't there a late production modification to the wiper delay unit, superseded to a non vacuum solid state unit which rendered the delay control on the column ineffective? Harvey?
 

harveyp6

Well-Known Member
#14
richj said:
Wasn't there a late production modification to the wiper delay unit, superseded to a non vacuum solid state unit which rendered the delay control on the column ineffective? Harvey?
Yes, very late cars had an electronic delay unit. Arthuy on here had one on a 2200 he had.
 
#15
harveyp6 said:
richj said:
Wasn't there a late production modification to the wiper delay unit, superseded to a non vacuum solid state unit which rendered the delay control on the column ineffective? Harvey?
Yes, very late cars had an electronic delay unit. Arthuy on here had one on a 2200 he had.
Ah, has anybody got any wiring diagrams, pictures, etc, of the later solid state type? :?: :D
 
#19
What a brilliant post. I too have had delay problems which occur intermittently.
Looks like I might have a shot at this.
Great pics and explanation
Many thanks for taking the time to put it up
Cheers,
John 71 P6B
 
#20
johnhoy said:
What a brilliant post. I too have had delay problems which occur intermittently.
Looks like I might have a shot at this.
Great pics and explanation
Many thanks for taking the time to put it up
Cheers,
John 71 P6B
Glad you liked it John. It's not too bad a job, just have plenty of rag around to clean out the old grease, if you decide to do the complete strip down of the motor :shock:
 
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