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Convertible top bleeding and filling.

93K views 20 replies 18 participants last post by  67redconv 
#1 ·
Big thanks to Bill Pritchard for taking the time to write this up!!

Since this topic comes up periodically, I thought I would type, verbatim, the wording of the factory approved procedure for filling the power convertible top reservoir with fluid. This comes from the Fisher Body 1969 Service Manual. I have inserted my comments in italics.


FILLING OF HYDRO-LECTRIC RESERVOIR


This procedure virtually eliminates discharge or spillage of hydraulic fluid and possible trim damage while filling and bleeding system.

Fabrication of Rubber Filler Plug Adapter


  • Obtain a spare rubber filler plug (Part #7596442). Might have to improvise here, as I’m sure these are no longer available.
  • Cut approximately ½” off male end of plug (end inserted into reservoir) to permit insertion of tubing as shown in sketch. Sorry, can’t copy the illustration from the manual.
  • Obtain a 2” length of metal tubing 7/32” OD x 5/32” ID.
  • Insert reworked plug into filler hole in reservoir.
  • Insert metal tubing through hole in reworked filler plug.

Filling and Bleeding Reservoir


  • On all body styles, with top in raised position, remove folding top compartment bag material from rear seat back panel.
  • On “B-C & F” body styles (full-size cars and Camaro/Firebird) remove rear seat cushion and back.
  • Place absorbent rags below reservoir at filler plug. Using pliers, slowly pull filler plug from reservoir.

IMPORTANT: When installing new or overhauled motor and pump assembly as a bench operation, fill reservoir with hydraulic fluid. This priming operation is necessary prior to performing the following steps in order to avoid drawing excessive amount of air into hydraulic system.

  • Install filler plug adapter to reservoir (already done in a previous step!) and attach 4 or 5 foot length 5/32 inch ID rubber tubing or hose to filler plug tubing.
  • Install opposite end of hose into a container of Type “A” transmission fluid.

NOTE: Container should be placed in rear compartment (trunk) area on “A” bodies (Chevelle, Cutlass, Tempest, Skylark) and rear floor pan on “B-C & F” bodies, below level of fluid in reservoir. In addition, sufficient fluid must be available in container to avoid drawing air into hydraulic system. (Again, an illustration is referenced here, but I cannot copy it into this document…sorry.)

  • Operate top to down or stacked position. After top is fully lowered continue to operate motor and pump assembly approximately 15 to 20 seconds, or until noise level of pump is noticeably reduced. Reduction in pump noise level indicates that hydraulic system is filled with fluid.
  • Operate top up and down several times or until operation of top is consistently smooth in both up and down cycles and no further air bubbles are exhausted in container of fluid.
  • With top in down position, remove filler plug tubing and remove filler plug adapter from reservoir.
  • Check level of fluid in reservoir and re-install original filler hole plug.

NOTE: Fluid level should be within ¼” of lower edge of filler plug with top in down position.

CAUTION: DO NOT OVERFILL.
 
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#2 ·
This is the procedure direcly out of the fisher body manual and for the most part it works well. However it cqn be adapted to give a better bleed. I found that by making a longer line of travel between the convertible top filler plug and the jar (place the jar on the floor or unbolt the pump from the bracket and lift it as high as the lines would allow you to) will able you to force more air out of the system. When I was finished I still had a couple of nasty air bubbles between one of the top fittings on the passenger side cylnderand the pump. When the cylnder was engaged for the up position the air bubble would flow back into the cylnder. Nomatter how hard I tried I could not bleed this bubble out. So I got a buddy to work the convertible top switch cracked the fitting bolt as he engaged the cylnder forcing the bubble out the fitting screw as well as a bit of tranny fluid and then retightened the bolt while the cylnder was still being engaged. The result a better bleed. Be careful as to not get any tranny fluid on your top. Good Luck.
 
#4 ·
All-

Great tech article! Much appreciated. Quick question though, how do you go about finding one of the filler plugs? I have to replace one of the actuator arms and will need to fill the pump up when finished, but I only have one filler plug. I was thinking if I jammed a 7/32" rubber hose and wrapped a rag around it to keep it airtight, then put the other end in the trans fluid, it shoud work?

Any suggestions?

Thanks,
John
 
#6 ·
This is weird. I am sitting aat a car show this weekend when I notice a fresh spot of fliud under my 67 SS convertible in front of the rear passenger side tire. It was coming from a steady drip off the frame. After checking the brake lines, all that was left was top hydrolics. I put the top back up and checked it out when I got home. The fluid was leaking out of the top of the convertible top cylinder. It does not look like it is going to be easy to replace the cylinder, but it looks doeable. I thought I would get on the Chevelle Tech Forum this morning and search the Archives to see if there was anything there on replacing the cylinder or for bleeding the lines. I checked the Convertible Forum first and the very first topic was Convertible top bleeding and filling. Whats the chance? I am assuming that everything in this detailed explanation of filling the bleeding the power top reservoir will apply to my 67. If you know for sure please let me know. Has anyone recently purchased a convertible top cylinder? If so who did you buy it from are happy with what you bought? Almost everyone has them but the prices vary by $10-$15 up or down. OPG says theirs is the best and made out of aluminum at $175.00.

Thanks,

Gary D.
Michigan
 
#7 ·
I have been trying to bleed mine for three day. I have the hose in the plug, and into the trans fluid container, and the fluid start going through the hose, but not steadily. There is more air than fluid in both the bleed line and the top lines ( a lot more). I feel like I am burning out the motor since there is not enough fluid in the lines to actually move the top.
 
#8 ·
Here's how I did mine with new cylinders. I took cylinders off mounts so there is no pressure on them, just laying in back of car. ran a hose from a funnel to the fill opening on pump, filled up funnel and ran pump so cylinders would raise top, took out funnel fill line and plugged with finger while pump had cylinders lower top, funnel only full when cylinders are expanding,did this just a few times, each time making sure funnel was full and you plugged hole on way down,. Don't try to bleed system with cylinders attached, too much pressure with not enough fluid.any?'s, just email me. good luck.
 
#11 ·
What happens if you disconnect BOTH lines from ONE cylinder and stick the ends of BOTH lines in a container of hyd fluid?
IT WOULD SEEM that the air would be pushed out of one line while the other line is sucking fluid and vice versa in the opposite direction.
Would this not work?

I need to know soon because the left cylinder has suddenly started leaking BIG TIME and I'm trying to get the car ready for CB10.

Last, if I can't get it fixed in the next few days, can I just unbolt the cylinder push rods from the top and raise/lower the top by hand?
 
#13 ·
Tom,
After disconnecting the cylinders I've been pulling my automatic top up by hand for years. With two people on each side it's pretty easy to pull the top up, just remember to start by pulling straight UP. While missing CB this year, I plan on getting the top working.
 
#14 ·
I made a filler plug out of a 1" long piece of 3/8" or 1/2" rubber gas line hose. My smaller hose to the quart of trans fluid fit inside it tightly and I ground the lower half OD down on my bench grinder until it fit tightly into the pump filler hole. Just a fat piece of hose and the tip ground down with my tubing jammed into the hole through the center
 
#18 · (Edited)
First timer with all this, rebuilt & restored my original top motor with a Hydroelectric kit. Real easy to do just cleaning and blowing out passages and installing new o-rings & large BBs. My car spent most of it life in rural areas of Mid Mi. The exterior of the motor casting and fluid reservior looked terrible opened it up motor windings, armature & brushes looked brand new! Reservoir side was a little gummed up cleaned up easy. Used some steel wool to refinish the exterior casting, painted the reservoir can with greenish Rustoleum self-etching primer with some VHT engine low gloss clear to match original finish (http://www.chevelles.com/forums/showthread.php?t=380967 ). Hardest thing about rebuilding the motor is reassembling, making sure the motor brushes are properly engaged. I also purchased a new plastic line kit & 2 new cylinders from Hydroelectric(they will match or beat other venders sale prices).

Also snipped the male end of the reservior plug to reveal a through hole and installed a 3" long piece of 1/4" O.D. K&S brass tubing along with removable plastic tubing cap(outside). Leave about an inch exposed to outside for filling and capping.

I took the cheap route and used some trans fluid i had left from a trans rebuild. I set the whole assembly up on a table. Using a clear ketchup type plastic bottle i prefilled cylinders lines and reservior as best as possible then test ran the sytem hooked to a 12v power supply. Used the 2 colored wires coming off the motor as (one or other hooked to +) up or down, black ground wire to negative on the power supply. Cycled it a few times and added more fluid to reservior then proceded to install whole system in the vehicle.

After installing i cycled it a few more times with cylinders not connected to top. Connected a 3' length of 1/4" I.D. clear plastic filler tubing to the reservior brass fill tube(tape tubing to the seat back reinforcment) it so it runs was vertical. Connected up the ketchup bottle(with trans fluid) to the 1/4" tubing and proceded to do final filling.Be prepared when you disconnect for little fluid backup. I found forcing fluid in when operating up or down worked best. You'll know when reservoir is at proper level because it will overflow with an airy/frothy mix of fluid. Your done, unplug surgical tubing add tubing cap to brass tube. I added a small nylon tie strap around the cap for added leakage protection.

Connect cylinders to the top mechanism and cycle it up down 4-5 times, your lines should eventually clear of any air bubbles and each side should operate uniformly. If your system hesitates a while before the cylinders start moving you may have a bad pump or you still have air in system either from a leak, air in lines or your still to low on fluid.

Using factory type clear lines allows you to see if you still have air in the lines or any kinfd of fluid loss.

This is my experience i hope this is helpful to others.
 

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#19 ·
Should the hose fittings on the top cylinders face the rear of the car with the top up, or the front? I still have air in the lines at the ends of the travel and am wondering if I have the cylinders oriented correctly. I'm not able to access my factory manuals right now, so I thought I'd ask here.

Thanks,
Scott in Colorado
70 Malibu Conv., getting new top.
65 Malibu Conv., pile of parts.
 
#20 ·
Cylinders should be installed with 90 degree hose fittings facing inward, lower fittings should be pointed up and slightly rearward, top fittings pointing rearward. fittings coming off pump motor should be inline with centerline of motor.
 
#21 ·
Filling the top reservoir with a large needle and syringe was plump simple. I have tried the plug removal method and it was a messy pain in the rear. I simply got a large syringe with a large needle and poked the needle thru the rubber plug and squirted in the oil. You create pressure in the reservoir and when you remove the syringe and leave the needle in ti releases the air pressure and helps bleed the system. raise and lower the top a little as you go and it will self bleed as you fill. I put almost a quart in in about thirty min. No mess no fuss. After I was done I Pulled the needle out and the rubber sealed back up like a medicine bottle no leaks a way easy.
 
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