We are going to have to wait for someone that has done this before.

I was able to turn the piston 90 degrees but it doesn't seem to want to pop out. BTW that spring is pretty strong.

 

OK DZRick ! dont'go any furthur till some one chimes in buddy.
Tell you what if i was 3500 miles nearer to Syracuse we go to find some jd weller 107 on me. many many thanks........ SAM.

 

If you ever run into Lee Phillips buy him a drink and tell him it's from his old Bermuda housemate.

I haven't indulged since 1990 but this does looks good.


This is what used to make me crazy. I keep a bottle handy in case sanity attacks.

 

some one please post pictures of pump piston especially from rear and side. and save us hitting the bottle...
please tell us how it came out of cylinder and how you get it back in.
we're nearly there now just need this last bit of help.
THANKS SAM.

 

ERNIE WILLCOX -Dr REBUILD ANYONE ?????????

 

Has any one got a broken old pump unit on the shelf they could kindly look at to see if plastic piston can be removed?Im sure some of the 350 readers would be also interested in this as it could possibly save us all a lot of time, money and frustration in the long run for the cost of a couple of o-rings and 30 minutes.
thanks SAM.

 

Hey Sam,


In this picture you can see a little slot in the back of the piston housing, I used a small screwdriver that I think broke the spring free allowing the piston to finally pop out.

 

DZ Rick, thats what i wanted, what do you reckon keeps the piston in by turning it 90 degree back again? it must some how lock to something in bottom of cylinder or on to flat actuator plate some how?
I know im keeping you busy but could you photo the back side of piston and if possible inside the cylinder then i can see for myself too.
A N.C.R.S. article written by Bob Cook a long time ago suggested piston just pops out when turned 90 but mentioned nothing else except to use multiple (2or3) o- rings to replace the original seal.Im wondering if it doesnt pop out because spring is off tension and maybee 2 lip seal just holds it back enough to require a gentle pull out?
We're just about home and dry now and boy do i apreciate all your time and effort.
THANKS SAM.

 

Your killing me Sam

The batteries in my camera died while taking those pictures and I put everything back together. This time it should be easier though and I can double check to see if you need to mess with that slot at all. Give me a few minutes.

 

Alright Sam, here we go.

This time I didn't need to take anything else apart nor did I have to insert the screwdriver into that slot. I'm going to edit some of my earlier posts in case anyone uses this post to figure theirs out, that way there shouldn't be much confusion.

This picture shows a couple of cutouts at the bottom of the piston. I can't see any reason for them, nothing in the piston bore that I can see has anything to do with them.

This shot shows where they are located in relationship to the "cross pieces" on the head of the piston.

Here is the piston bore as you will see after removing the piston.

When reinstalling the piston you will need to make sure this is pushed toward the piston assembly as far as possible.

Now the inside will look like this.

The little bar closest to the front of that photo locks into the piston when you turn it 90 degrees, you can almost see how in this shot.

 

Well DZ Rick,
We got to the final whistle THANKS TO YOUR SPLENDID EFFORTS and to all the other replys too.
Bet you cant buy a replacement double lip seal/o-ring though!so its doubled up single rings.
Recon this topic could make a good technical paper for some one to do.

My best regards and MIGHTY THANKS SAM.

 

I was happy to help you out and since I had the part lying around it was a good excuse for me to tear it apart and learn something myself.

Hopefully you can find seals that will work.

 

Any idea how big that notch in the toothed wheel is supposed to be?
My 74 spans almost 50%

 

My top edge notch is about 3/4" inch in length not 50% of circumferance and pump works perfect,se DZ Ricks other photos his is about the same also,if you got problems it could be this.The plastic cam i dont thing is avail except from a breakers yard G.M. used this system on other cars ie.Camaro,Chevelle.etc so scavenging a cam may be possible.

 

Here are the two I have.

 

Mine looks more like the second one, no c-clip.
I'll see if I can take a pic tonight.
My problem is that it's not grabbing the first time, if I manually push it one click,it circles around and pumps no problem.
Thoughts?

 

Now im no expert on these pumps but what i gather is the second picture is a later design prob. 1971 72 73. the first pic prior to this im not sure of the revolutions for pumps that actually pumped to the headlights as well as wipers. May i suggest creating a new post on this as im sure members will be interested in this partially misunerstood topic and i would not wish to miss lead on somethig im not sure of.
Regards SAM.

P.S. your profile indicates a 1974 model, mine's a 72 and my cam looks like DZ Ricks second pic no c-clip and with internal spring. I suspect the first pic is a earlier pump ie.68/69/.??
.
There are 2 return springs are they in situ, not weak/rusted?
Are the teeth on the plastic wheel wedged ie not rounded off? and clean.
Is the catch gate that grabs the teeth off centered up or down check the spring,its easy for this to be out ,re align with fingers if not damaged.
There is a vent slot on rear of plastic cylinder,if water is present around this area or around actuator bar slot good chance piston o--ring is worn and passing water.If the pump has been removed from washer motor the underside plastic drive arm cam slot must be aligned correctly with drive pin on top of WIPER motor
by means of a nail thru hole in pump base plate (ref workshop chassis manual)
when pump is remounted.
Is the dog pawl (white plastic retained by screw) next to base of pump cylinder lose or gunged up or broken?
Hope this is of help.

 

Started a new thread specific to my issue
http://forums.corvetteforum.com/c3-t...-part-2-a.html