Top Fill Procedure

**sjgreen6** · 05-19-2010, 04:49 PM

Thought I pass on some bits I figured out this past weekend. My top was running slow so I figured it needed some fluid. A couple of searches turned up the info that GM says to switch to mineral oil instead of ATF. I still haven't seen the TSB on this so if anyone has it I'd appreciate a copy. In one of the earlier posts someone suggested that you can look up the procedure in the owner’s manual. At least in the 2002 version there isn’t any information on how to fill the pump. There is info on using the manual control valve but that’s pretty much the extent of the info. Perhaps I am missing a convertible top supplement? If so someone let me know.

This applies to a 2002 Firebird so it is probably good for 98-02s. I started with a quick look with a flashlight through the little cover flap on the inside left panel to confirm that the valve was fully in the correct position to operate and the fluid in the tank looked low. When in the run position the valve should be 90 degrees to the block on which it sits. When the valve is moved 90 degrees to the right (clockwise, it only moves one way) the system pressure is released and the top can be operated manually. The valve should always be fully one way or the other depending on what you need. As a note I started this process with the top up.

Next I carefully removed the cover on the left side by sliding it out from under the edge and behind the other cover pieces. Hardest part was getting it out from behind the CD player as the wiring harness could be damaged if you aren't careful.

An inspection with the flashlight showed some oil on the pump base plate and in the well. Either I had a leak or someone missed the hole when previously filling the pump, I wasn't sure. I decided to remove the two nuts that held down the pump base plate and was able to gently lift the pump and base plate off of the studs and out of the well while still connected to the wiring and all of the hoses. I sat the base plate on some towels to protect the rest of the trunk area (CD player ended up being a great place to set mine while checking it out).

I wiped down everything and found probably a couple of tablespoons of ATF in the well. The pump tank has two lines for min and max fill (not labeled but makes sense). Using a line wrench I carefully snugged up each fitting on the pump being careful not to stress any of the fittings or lines.

I decided that I wanted to remove as much ATF as possible and replace it with mineral oil. From what I have read in several places GM decided that the ATF was not the best for the top ram seals and has recommended mineral oil. I moved the pump valve to the manual position to release the system pressure then using a hex wrench I removed the filler cap that is on top of the pump tank just in front of the valve.

I used my Mityvac with a long thin hose to suction out as much of the AFT as I could get. You could probably get away with a suction bulb and tubing but it would be messier. Then I released the top and manually lowered it to the fully down position which pushed more fluid out of the system. I removed this fluid as well then refilled the tank to the max line with mineral oil that I picked up in the pharmacy section of a local store. I then manually raised and lowered the top several times to circulate the fluid. The fluid that returned to the pump looked more like ATF than mineral oil at this point so I went through the drain and refill process several times to get as much of the ATF out as I could. In the end there is still some ATF color to the fluid but I’m satisfied that it is better than 90 percent mineral oil and the two fluids don’t seem to be separating.

When I was done with the fluid change I switched the pump back to the run position and with the top in the down position had an assistant start the car and push the button to raise the top. It took a moment then the pressure seemed to come up and the top went up just fine. Watching for leaks while the top went up and down several times I found none. I also had my assistant stop the top in the half way up position for a moment so I could check the top seal of the rams (looked with a flashlight between the folds on each side of the top mechanism) to ensure there were no leaks there, good to go.

With the top in the full up position we shut off the car then replaced the pump and base plate back on the studs and snugged down the nuts. Note that the studs go through rubber grommets that reduce the vibrations when the pump is running. These are a common size and should be replaced if deteriorating. There are several grommets on other spots on the base plate that do not sit on studs and if one of yours at the grommet position is worn you might just be able to swap one around to the more critical spot.

Last I filled the tank to the max position. It is important to do this with the top up. If you fill to the max with the top down, when you raise the top you will end up below the min level. When you lower the top the fluid will show above the max level but not more that the tank can handle so my assumption is that you check the pump level with the top in the up position. Do not fill above the max level with the top up as you could end up with more than the tank can handle when you lower the top, it’s pretty close when all of the fluid is pushed back into the tank when the top is down.

Final report is my top now works better (responds immediately when the switch is pressed and is faster in each direction) than it has since I bought the car and I cannot see any leaks.

Hope this helps.
Steve

**TRANS-DAD** · 05-20-2010, 07:33 AM

WoW!! nice write up!....very good info!!

**Y2KPewterSS** · 05-20-2010, 08:50 AM

Good thread

**thearborbarber** · 05-20-2010, 07:03 PM

Sticky worthy

**jb3golf** · 10-09-2010, 11:11 PM

Nice write up. My top stopped working about 4 months ago and I haven't bothered to figure it out; looks like my issue may be no fluid......

**sjgreen6** · 10-11-2010, 01:00 PM

Be sure to use a manageable bottle or long hose with funnel to get the fluid in the pump. It is easy to dump fluid all over the pump and into the inside of the fender. After that do the manual raise and lower a few times to push the air out of the lines then refill the pump until it stays at the full line in the up position.

Also look for leaks at the pump and with the top down look down the sides of the top at the lift cylinders. That fluid didn't evaporate, it went somewhere and you need to find the leak. If you are lucky like me it was a leak at one of the pump fittings and not at the lift cylinders. The pump is a lot easier to diagnose and replace if necessary.

Good luck and let us know how it turns out!

Steve

**OBX TA** · 10-28-2010, 10:17 AM

Great write up and thanks for the detailed information. I havn't had any problems with my top going up or down, but since it's not a daily driver, the top stays mostly down anyway.

**TRANS-DAD** · 10-29-2010, 03:52 AM

Originally Posted by OBX TA

Great write up and thanks for the detailed information. I havn't had any problems with my top going up or down, but since it's not a daily driver, the top stays mostly down anyway.

Ha Ha! yep! I do the same!..., My car's not my daily so most of the time the top stays down & I just pull a car cover on it!....

Still a great write up tho!!!!!!!!!

**sjgreen6** · 10-29-2010, 04:40 PM

Didn't break 55 degrees today but was so damn beautiful and sunny I had the top down every leg I drove. Just something about blasting around in a Vert!

**OBX TA** · 11-09-2010, 07:38 AM

With the top up, I feel so closed in. I bought a vert so I could have the top down and enjoy myself, whether its' warm or cold. Sounds crazy but I'll suppliment the ambient temp with either the AC or heat depending on the season. No, I'm not very "green", I just enjoy the outdoors.

Keep the top down!

**sjgreen6** · 09-16-2011, 05:41 AM

Found the GM Bulletin that directs you to change the fluid from Dextron to light oil.

Document ID# 911168
2001 Chevrolet/Geo Camaro
Service VME - Convertible Top Hydraulic Fluid #PI00386 - (Aug 14, 2002)
Service VME -- Convertible Top Hydraulic Fluid.
When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.
SERVICE VME
This is a service VME to all Chevrolet and Pontiac dealerships regarding 1994 through 2002 Camaro and Firebird convertible top hydraulic fluid. This is Art Spong, Brand Quality Manager for the F-cars. The service manual and ESI incorrectly advise to use DEXRON® III automatic transmission fluid for the hydraulic fluid in the convertible top system. The proper fluid is a ten-weight SAE oil. A bulletin will be issued and ESI will also be corrected. Thanks. If there are any questions, I can be reached at 586-947-8890.
Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

STRUCTURE:BODY:ROOF AND PILLARS
Bulletin Date: MAY 2002
SERVICE MANUAL ADVISES INCORRECT USAGE OF CONVERTIBLE TOP FLUID. ( NHTSA ITEM NUMBER - 636700 )