[dreamta1972]

I recently acquired a '68 LeMans convertible. I have never owned/worked on a vert before. motor runs,but top doesn't move.
1) Where do you access motor to add fluid?
2) IF it has brake fluid and I wish to change to ATF,what is the procedure for draining brake fluid and bleeding?

Thanks

[nytrainer]

I have 2 ‘68 convertibles. My advice would be to remove back seat (bottom, then top) and you should be able to see the motor (might have a cardboard panel to remove). Then I’d remove the lower side panels (they’re attached to the panels that cover the top mechanism) to get a good look at the interior lines (hoses) that feed each top cylinder (they route through the seat back vertical panel into the trunk as well). Fluid could be leaking at top or bottom of cylinders or through the hoses themselves (cracked, brittle, pinched..). Looking into the trunk at the motor from inside the car the fill plug is on the left side of the motor. You can easily tell from the smell of the fluid if it’s brake fluid but seems, to me, that most times I’ve come across ATF filled systems. I use small vacuum hose sized clear tubing to add ATF. Chances are good that you’re just low on fluid. I just so happen to have one of mine with seats and panels removed if you need pics. Let us know what you find.

[Stuinnh]

Just had this problem when I got my 68 convert. Hard part is bleeding the system correctly. If not right won't go up.

[nytrainer]

If you’re just refilling and bleeding I like to disconnect the top of the ram from mechanism (9/16 nut and bolt) and run the fluid through the rams (lift cylinders) without the resistance of the weight of the whole top assembly. I find it best when bleeding to fill reservoir on motor while the rams are fully recessed into the cylinder housing. Leave fill plug off and Then try to run the motor to extend the rams (switch to down position), then run rams into housing again and refill. Keep this pattern until they both extend. It’s common for only 1 (seems passenger side) to pump up first but if you keep cycling (and refilling only when ram is fully into the cylinder) you will eventually bleed of the air and have a working top.

[Scott Thelander]

and have a BIG bag of kitty litter just in case

and rags

[Peter Serio]

I have owned close to 1/2 dozen older Pontiac convertibles in the past 35 years. Just FYI, Once a car is past the 50 year mark adding fluid is probably not going to revive a non-working power top. If the original factory fill fluid was brake fluid all the interior parts of the hydraulic system are now corroded. Old brake fluid (sitting for years) will lock-up the pump motor and it will also freeze both lifts in-place. Once those lifts have sat for years in the same place they tend to lock-up anyway. If you suspect that the car had brake fluid in it to start with I would convert the car over to ATF. You will need to replace both lifts, the electric pump motor (complete) and the plastic fluid lines with all brand new parts. MAKE SURE THAT YOU BUY HIGH-QUALITY top parts, do not shop "price" shop for something good from a reputable company that comes with a guarantee!!!! You may need to pay a little more up front but, trust me, it's worth it in the long run.

There is no way to flush out all of old brake fluid from a 1960s GM convertible and mixing even a little bit of that old stuff with fresh ATF would be bad. NOTE: When the lifts are removed you want to manually cycle the top's folding steel arms up and down; several times (this will not be easy as that top is very heavy). You may need 2 people to do this.


You want to make sure that the folding parts of the roof support assembly are meshing and stacking properly. I've gotten into several cars with bent or broken counterbalance arms, top forward header and/or link arms not adjusted properly. Cracked body welds around the stack well (in behind the rear seat) are pretty common. I have also seen many cars with missing, cracked, broken and/or worn out bushings as it relates to the folding part of the top. If you do not have a good folding side arms to the top assembly the new hydraulics will not last very long.