Wiper Door Installation - 70

[Roger G.]

I am reinstalling my wiper door after being off the car for many years. Question on how tight the pivot bolts should be. I found if I put the pivot bolts in loosely, the ones which hold the door to the lift mechanism, it seems to work OK. If I tighten them at all they bind.
Is this normal? Wondering if I may have too much paint build up around the holes where the bushings are located. The lift mechanism has been throroughly cleaned and repainted. If this is typical, do people use thread locker to keep them form backing out over time?

While I'm at it. Anybody know when to use shims, the ones for mounting the lift mechanism to the firewall? To keep the gap between the wiper door, grille, and end of the hood even? Or is it to avoid bending the shaft slightly when the mounts on the firewall may not be perfectly in line? Assuming any misalignment may cause binding.

[Bill L.]

Re: Wiper Door Installation - 70

HI Roger,

I reinstalled the wiper door on my 70 last month.

Make sure you have two bushings.

The bolts are a kind of shoulder bolt to prevent them from going in to far.

I had no problem using the correct washers and bolts.

Hope that helps.


Bill

[R N.]

Re: Wiper Door Installation - 70

Bill's spot on. Two bushings and be careful as it can be tricky to fit everything together in the space you have to work with. I put a rag or the likes under the door in the wiper bay because if you drop one of those screws or bushing, it will drop onto the rag and not down into the plenum were you may not be able to retrieve it.

[Roger G.]

Re: Wiper Door Installation - 70

HI Roger,

I reinstalled the wiper door on my 70 last month.

Make sure you have two bushings.

The bolts are a kind of shoulder bolt to prevent them from going in to far.

I had no problem using the correct washers and bolts.

Hope that helps.


Bill

Bill's spot on. Two bushings and be careful as it can be tricky to fit everything together in the space you have to work with. I put a rag or the likes under the door in the wiper bay because if you drop one of those screws or bushing, it will drop onto the rag and not down into the plenum were you may not be able to retrieve it.

Thanks everybody. I did drop one bolt down behind the fender, no way to get it back.. I now remove the entire linkage, put the door on, then reinstall as one piece.

I do have two bushings on each pivot, 8 bushings in all. The bolts and bushings are new. I am finding that if I tighten the bolts, the joints tend to bind a bit. Works smoother if I leave things a bit loose. Doesn't seem right. The linkage and door are original to the car, all I did was to have the linkage sandblasted years ago. Recently I went over all the linkage, primed and painted. Had to free up the spring loaded arm which was frozen.

I noted the shoulder of the bolt extends beyond the outer bushing but not by very much.

Should the wiper door move freely when installed or should it have a bit of resistance?

[R N.]

Re: Wiper Door Installation - 70

IMO, the door should move freely.


When I did my buddy's '72 I used the bolts/screws from Paragon and all worked well. Maybe your hardware is off????

[Jim T.]

Re: Wiper Door Installation - 70

Thanks everybody. I did drop one bolt down behind the fender, no way to get it back.. I now remove the entire linkage, put the door on, then reinstall as one piece.

I do have two bushings on each pivot, 8 bushings in all. The bolts and bushings are new. I am finding that if I tighten the bolts, the joints tend to bind a bit. Works smoother if I leave things a bit loose. Doesn't seem right. The linkage and door are original to the car, all I did was to have the linkage sandblasted years ago. Recently I went over all the linkage, primed and painted. Had to free up the spring loaded arm which was frozen.

I noted the shoulder of the bolt extends beyond the outer bushing but not by very much.

Should the wiper door move freely when installed or should it have a bit of resistance?

Roger if your 1970 is not air conditioned you do have limited access to both plenums if you remove the metal vent doors and have small hands or have someone with small hands find the bolt. A magnet could be used. Only the passenger side vent door is removable on air conditioned 1970 Corvettes, the drivers side is sealed.

One thing about removing the vent doors you might be tempted to replace the sealing material supplied by Dr. Rebuild.

[Roger G.]

Re: Wiper Door Installation - 70

Hi Jim,

Thanks for the tip, wondered if that was an option.
I had another set of pivot bolts so I'm not in a rush to try and dig this one out.

I did try fishing for the bolt using a magnet on stiff cable. Didn't find the bolt but found a trim clip and a screw which had been dropped down there years ago... based on the rust they appear to have been in there a long time.

[Roger G.]

Re: Wiper Door Installation - 70

IMO, the door should move freely.


When I did my buddy's '72 I used the bolts/screws from Paragon and all worked well. Maybe your hardware is off????

I found that if I loosened the bolts holding the door to the linkage I could get the door to operate though a bit sluggish reaching the point where the wiper safety switch tripped. The linkage had been sitting for almost twenty years, spring tensioner portion was seized. Quite an adventure getting it freed up, took hours of intense twisting to get it loose. Thought I may break the unit given the force it took to get that sleeve to free up. That part works freely now. Questioning whether the other joints have stiffened over time.

Wondered about a possible misalignment between the pivot bolts and linkage but it seems unlikely. The door and linkage are original to the car. Worked fine when I bought the car. Only thing done to the door was cleaning the threads with a tap. No new holes, no helicoils, etc. The bolts can be tightened without stripping threads so I doubt the hole has been enlarged. The slight bind I get when tightening the bolts may be just enough to cause the until to get stuck, combined with stiffness in the linkage.

I tested the theory of the bolts being an issue by removing all bolts but one and testing the freedom of movement. Some moved quite freely, one or two others move with just a bit of stiffness but certainly not jammed.
My thought now is the linkage still needs work, too stiff. The joints on the ends feel a bit stiff to me. I'm thinking the extra drag introduced by a pivot bolt or two may not be the root problem, only enough when combined with a somewhat stiff linkage unit to cause the door to hang up.

Does anybody know of anybody or a place whom they can recommend to disassemble, replace the rivets to regain freedom of movement?

I saw one vendor offering a repro version. I hesitate to consider given the quality issues I hear of. I also noted a vendor offering a reconditioning service, cost unknown.

[Joseph M.]

Re: Wiper Door Installation - 70

I also read somewhere to put some loctite (non permenent) on those bolts as the they tended to loosen after time and use.

[Roger G.]

Re: Wiper Door Installation - 70

Three years later I'm still wrestling with this issue.
I took the entire unit out of the car, clamped one end of it to my workbench to keep it steady.
First off I see there is a small gap between the pivot arms and the wiper door before I tighten the pivot bolts.
The door moves freely until I tighten the bolts. When I tighten the bolts I see the pivot arms being pulled outward closing the gap between the bushing and door.
This seems to cause a bit of binding. The pivot arms do not have much play side to side. I'm assuming the distance between pivot arms must be pretty precise to fit without being too far apart or not enough as mine see to be. I can't see how my linkage could become shorter nor do I see anything which appears to be bent.

Should the door move as freely with the pivot bolts tight as it does when they're loose?

I can lessen the bind if I put #10 lock washers between the outer bushing and the door. The gap I see is about the thickness of a #10 lock washer.

Should the pivot arms have more side to side play? The door looks OK. Maybe there's something bent or twisted in the linkage?

[Mark E.]

Re: Wiper Door Installation - 70

I ran across this unanswered thread while researching R&R of the wiper door.

Did Roger determine the cause of the binding between the pivot arms and wiper door? Is some side to side play normal? Or should the mechanism work freely with the bolts tightened?

[Roger G.]

Re: Wiper Door Installation - 70

Hi Mark,
I wound up buying another linkage assembly, think the surfaces inside the bushings were rusted, contributing to a bit of binding. The replacement unit was a bit less stiff at the end of travel but still bound up a bit. I shaved the flat surfaces on the nylon bushings using a piece of emory cloth. I'd guess I took off maybe 0.005 inches. I can now tighten the bolts without binding, working great.

[Mark E.]

Re: Wiper Door Installation - 70

Good deal. I have the project of reinstalling a wiper door ahead of me, so I may look to your experience.