Washer/Wiper Problem Found. But how to fix?+Photo

[Juliet P.]

I've been battling a washer / wiper problem which completely failed on the way to the NCRS meet to have my car judged a few weeks ago. Initially I thought it to be a vacuum problem with the valve at the base of the passenger wiper. Then I thought it to be an electrical problem with either a switch / relay or fusible link. However, it's neither a vacuum, nor an electrical problem, but rather a mechanical one with the washer pump causing the wiper motor to bind up. :(

In the washer pump's past life the little cog wheel on the Outside of the system has a nibble out of it. I checked my photos of the pump when I first disassembled it, and the nibble is missing there too. Encouraging that I didn't break that part, but a bummer nonetheless. You might be able to make it out in this picture. The notch is missing between about 4:00 and 6:00 in the center wheel below.







For those of you who haven't seen the guts of one of these things before, the wiper and washer are linked together with the cog wheel. When the wiper thing goes around, and the washers are activated, they rotate together. The picture below is the wiper part, where you can see the piece sticking out. This fits into the cog and moves the piston on the washer pump.







What happens is that as the cog piece rotates and on the other side the plastic piece (the broken part with the missing notch) piece rotates. There's a metal arm which rides on a varying height shoulder just below the upper edge. I think this shuts the thing off after one complete cycle. Anyways the metal piece which rides on the shoulder gets snagged inside the plastic piece, causing the wheel to lock up. Apparently during my cleaning & relubing process I removed the old dried gunk which had been keeping the extra metal part separated from the plastic somewhat, preventing it from easily sliding in the inwards radial direction. Upon nicely lubing the thing up it now slid freely inwards and got caught up on the broken part. I hadn't tested it before, only lubed the parts since I didn't want to loose the correct cog position to reattach it to the wiper pin. Otherwise I might have noticed the broken notch a few weeks ago. But I didn't. :( Anyways, I will need this replacement plastic piece. Does anyone know if the 3 port system contain this as innard pieces?

Unfortunately while diagnosing the problem by manually turning the cog wheel (on the inside of the washer pump) shown below:







I manually turned the cog one time to many, and the plastic molded piece at the base of the piston, which holds the connecting rod to the piston shattered over the 2 connecting arms. :( This of course sent the heavily rusted spring and plastic piston flying across the garage, :eek: which of course sent me on a frantic hands and knees search for said spring & piston. :p I found them both fortunately. :) The ironic part of this all is that the piston & pump were filled with water, which means that the assembly had at least successfully pumped some water during their initial pass! :) Bummer that it's shot to he$# now. :(

I can't imagine the plastic epoxies holding those two broken bits (I have both) in place so it looks like I'll need a new piston assembly too. MEGA unfortunately, I'm afraid that this :( is one of those 1970 only sized parts :( which only comes with the 5 port washer thing. :( Which is of course IMPOSSIBLE to find for anything I can pay! :( :( :( I'm 90% sure that the 3 port piston is a larger diameter since the rebuild kits all have a huge honkin' gasket for the pistons. :( :( :( Needless to say I'm totally bumming about this. I sure hope someone can tell me if there is some other GM (or any brand for that matter!) part which has the right diameter piston for this thing, or some way to get one attached or something. I suppose if worse comes to worse I'll have to see if Uncle Don (our former neighbor who is a master machinst with a NC mill in his garage ;) ) can machine one up for me from aluminum or something like that. :) :) The NCRS guys will never see inside the plastic housing so that might have to be my fall back position.

Right now I took the inside cog wheel off and put the thing back together so that my wipers are functional at least. :) I need to decide whether I should put my original vacuum valve at the base of the pass wiper back on, (I think it still works :cool: ) or go with the GM replacement. They are subtly different. I'm not sure if any NCRS judge would check or notice. Yes I'm splitting hairs here, but I'm also chasing NCRS points... and believe it or not lovin' it. :D

Oh well, I'm off to read the new posts and see what corvette adventures the rest of you all had today. :) ~Juliet

PS, Trying to figure out how to inline the photos. You might need to cut & paste from your browser to get to them.

[Juliet P.]

Cool, the Photos in the message worked!

Cool! The Photos worked! :) BTW, I just inserted html code into the post incase any of you web junkies were wondering. :) ~Juliet

[Jack H.]

Re: Cool, the Photos in the message worked!

What some refer to as the 'Nautilus' assy should be common across 3-port and 5-port pumps unaffected by the size of the unique 5-port washer piston. The material, I believe, is Delron -- a form of self lubricating nylon commonly used then and now in plastic mechanics that see repetitive abrasive stress....

When I re-worked my ('71 3-port) pump (Corvette pump is unique due to pin-out of pwr supply terminals to safeguard against shorting in the Corvette shield distributor/air cleaner environment), I simply walked on down to my local scrap yard, picked up a 'choice' looking washer pump out of their re-cycle wiper motor bin (the rebuilders have a 'scalp' fee for cores and they don't give a darn whether or not the wiper motor has its washer pump in place) and paid a whooping $1.00 for three unit fee....

At home, on the bench, I donned my executioner's hood and proceeded to dissect a sacrificial wiper pump to see how the drive gears/cogs would come apart and found it was pretty painless! BUT, beware to carefully note the relative geometry/placement of individual pieces to the assy as a whole, because once you've got 'er stripped down, you'll wonder if there's a right/wrong orientaion for final assy, and in some places there IS! Plus, if you forget or loose your crip notes, you can always fall back upon the trusty Chassis Service Manual that has GM dissassembly photos in it showing the relative position of things in their normal, at rest, orientation.

Buena suerte, amiga! as our friend south of the border say....

[Juliet P.]

Yeah, but Jack...

... that will probably work for the circular piece. WHEW! Thanks! But... the diameter of the piston for the 5 port is different from that of the 3 port. The 5 port piston is smaller. I have a 3 port rebuild kit from Zip and the piston gasket is about 1/4 inch too large (unstretched at that). From that I deduct that the 5 port piston and 3 port pistons are physically different diameters. Looks like I'll get to hit the junkyards for the other part. :) Glad to hear those are "find-able" still. Thanks, Juliet

[Jack H.]

Only talked....

about the 'Nautilus' drive system. Youse guys with the 'odd ball' 5-port piston/cylinder simply have to bend over and open the old wallet!!!! I see the 'viscious' argument frequently (dude with '70 going up against dude with early '71 where two the five ports were blinded) where folks fight over who has the REAL NEED for this unique part. Bottom line, tain't no right answer and, to my knowledge, once Delron has terminally fatigued itself there's no good/lasting fix. Stuff is 'slithery' and wants to fight bonding from conventional glues. I know where there are three bona fide 'spare' 5-port pumps in town, but the opening bid STARTS at $350.... Good luck!

[Juliet P.]

Well that really BITES!

Thanks for the info Jack, but bummer bummer bummer. I was afraid that the piston was one of those lessons in supply (low) and demand (high) parts. Yukko. I never enjoyed my economics classes anyways.

OK, I'll just console myself that the nautilus part is obtainable. :) Now Jack, the nautilus isn't the other side where the wiper shaft rides in, the softened point four star piece? That's the part with a sorta spiral deal on the attachment thinggey... The natuilus is on the front of the car side of the washer assembly? It's the one direction cog wheen thing?

Looks like I'll be trying the machine shop version of the piston. With a limited budget, there are just too many other pressing items to fork upwards of $300 for a silly little piston. (groan...) Oh, to finish up this degree and get a huge raise (she says kidding herself) to buy more corvette parts. ;-)

Anyone forsee any problem with using a teflon (strength) or aluminum (compatibility) fabricated piston? Or is the Delron available in solid form and machinable? What other types of materials might be suitable for fabricating a replacement piston? Or is it possible to make a new base plate for the piston somehow and epoxy it to the base of the existing piston? Hmmmmm, there's got to be an engineering solution to this. :-) I've got pretty easy access to machine shop equipment and machininsts who know how to use them, it's just a matter of appropriate material choice.

BTW, does anyone know how they got the piston rod into the back of the piston in the first place? It wouldn't appear from mine that the ears will fit through the opening. Unless they were press fit just once? ~Juliet

[jbs75]

Re: Well that really BITES!

don't know about the rest, but your machinist would probably rather machine the delrin, MUCH easier. have had lots of experience having parts made.

Jim

[Terry M.]

Re: Well that really BITES!

Juliet,

I believe Delron is available and very machinable. There is also some stuff (boy will that make the engineers cringe) called UHMW plastic (ultra high molecular weight) that is used for making jigs in woodworking and I bet other applications. Some of it might be Delron or close cousin. Great stuff, slippery as all get out, very machinable if you can hold it down, not inexpensive. Might be available at craft places or stores that cater to wood workers.

Terry

[Gene M.]

Re: Well that really BITES!

Delrin is an acetal, the surface is slick, "nothing" will glue it. The surface is not hard if machined. The delrin is notch sensitive when machined and may break at stress points. Another material Nylon 6/6 is sorta machinable but feathers and absorbs water over time and will swell. But it is tougher skinned when machined for wear. Nylon is also not glue receptive. Both will accept light press fits, better on a straight knurled pin. ABS is another material that machines and solvent bonds well, but again is not hard skinned when cut.

[John M.]

Re: Well that really BITES!

Juliet,

I have Delrin and an even slicker thermoplastic called Bearing grade Torlon. They both machine like a dream and are probably a lot stronger than the original material.

Tell me the rough diameter that you need and I'll send you a piece.

[Juliet P.]

Materials Science Lesson here & Thanks!

Gee, this thread reads like a materials & manufacturing engineering textbook! Will all the techies on this board I should have predicted that though. John thanks for the offer! What a pal! :-) I've just send you an e-mail.

BTW, incase anyone is curious, the rough measurements of the original 1970 washer pump piston are 1.0 inches in diameter and 7/8 inches in overall length. Thanks everyone! ~Juliet

[Juliet P.]

Who taught me grammer?

Geeze, What I should have written is: I've just sent you and e-mail; or I'll send you an e-mail. I'm starting to write just like George Daina writes after he's been listening to too much that crazy music of his.....

[Jerry Clark]

Re: Well that really BITES!

Hi Juliet:

As Terry said UHMW is a wonderful material and would work well in this application. It can be found in most gourmet cooking supplie stores in the form of cutting boards and any company that produces material handling equipment, (conveyors) as it is often used as a guide material, all but friction free.

jer

[John H.]

Don't Sweat the Grammar!! Just Tell Me......

.....how you did that picture thing, which was REALLY impressive and made your dilemma easily understandable. I'm a 20-year computer builder/user, but I can't write code and don't know squat about HTML. Neat thing - howdja do it?

Thanks, John

[Ol'Geezer]

Re: Don't Sweat the Grammar!! Just Tell Me......

I have tried to learn a little HTML from www.webmonkey.com I think that she might post a photo by: Let's see if that works. Geezer.

BTW, my new one was delivered Friday. It can be seen at


Geezers Cars