petecaballero

Hi, my 1986 has very slow windows. Should I be looking at replacing the regulator assembly or can it be something else?

antfarmer2

Try clean and lube first.

jay23ls

I want to chime in here bc I too have a slow window (driver side). It will not go up sometimes on the first press and recently it got stuck, had to "spot" the motor and helped it close the window w/ by pushing it myself upward.

I checked the service records and it shows repeating problems

Left (assuming driver side) motor power connector repaired - 60k miles
Left motor replaced - 79k miles
Left motor replaced - 93k miles (car has 94 right now)

Maybe I have the sides reversed and that was all passenger motor work done? Is that common to have to have had a C4 window motor replaced twice under 100k miles? Thanks

antfarmer2

Sound like something was sticking or not working smoothly burning up motors. My 94 has a bit over a 100k and both original.

HAD2HAV2

You can use WD40 on the metal coil spring. Use CRC Di-electrical grease, Lithium grease, or synthetic grease on the rollers and the shafts they move in.
Pull the door panels off being careful with the power door lock connections.
The old grease hardens over time with heat.

FOURSPEEDVETTE

How would you go about this procedure?

jay1055

First generation C4 window motors are all slow you can upgrade to later motors but not sure what year they changed them. Jay

Benny42

My '86 had the old style tape drive window regulators. I tried every trick to speed them up
with various lubes. None helped. I replaced both sides with later model regulators, fixed and
very reliable. The tape drives are just bad.

petecaballero

Benny did you have to modify anything. I have been told that even a 1994/95 would work but I am concerned that it might now be a direct fit. Was it a lot of trouble to go to a later model regulator?

Cliff Harris

I upgraded the old ribbon style window regulators with the newer ones. The instructions say you have to drill mounting holes in the bottom of the door but mine already had the holes. I have an early '86 (December 1985). I heard the late '86 cars had the improved window regulators.

Joe C

I updated my 85's ribbon style to the later design - in my case, i'm thinking 87 regulator assemblies (at least what I remember from the date codes). installation was fairly straight forward - only had to drill two holes. mid-america corvette has excellent, on-line, tech instructions.

helpful links -

http://forum.grumpysperformance.com/...php?f=35&t=103

http://forum.grumpysperformance.com/...hp?f=35&t=2072

I understand even later designs had improvement, but in my case, i'd guess both sides have about a 2 sec travel time. IMO, one of the best updates for early C4's. even solved my glass rattle problems!

Benny42

It was very easy. You won't regret it one bit.

Dt86

I also upgraded to the newer style regulators and also added the later window guide rods to eliminate the window rattle. Not a difficult project. On mine the wiring had to be reversed for the passenger side regulator since up on the switch went down on the window lol.

JrRifleCoach

Like the others, Clean and lube the tracks and pivots.
Check and clean the motor connector and contacts as well.
IF your passenger side is a tape ribbon, replace it now!
You can find the replace tape in the "emergency" section of most parts stores.

Barchetta

Spray the window runners with a silicone spray lube. Silicone lubricant won't wash off as easily.

DinoBob

I also have a December '85, VIN last six are 16868.

DinoBob

Adding, I cleaned and greased my tape regulators and tracks completely and with white lithium grease, and they seem fine to me.

JrRifleCoach

I believe the Pace Car production start was where the a bunch of changes occurred. The AL head L98 and lots of small changes like the passenger window scissors. The drivers side was scissors from the start of 86 production.

DinoBob

Not from my experience. I have had both of my doors open and both are ribbon regulators. Build date 11/20/85.

Dt86

Pretty certain that all convertibles came with the upgraded regulators. Which is probably why most 86 doors are already drilled for them.