R. Todd Rothrauff

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  1. The Rides . . .
  2. 1996 Jaguar XJS convertible . . .

April 21 - May 6, 2017: Replacing the convertible top cylinders . . .

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  • A few months ago, I tried to lower the roof on the XJS.  The first clue I received that something was wrong came in the form of a strange noise from the convertible top pump motor.  It made a noise that seemed to suggest the system was low on fluid.  But the roof lowered the way it was supposed to do, and I didn't give the matter a second thought.<br />
<br />
That is UNTIL I saw a trail of red fluid under the right side of the car after I pulled out of the garage.  So I've got a leak somewhere. But unlike the incident with the XK8 last year where leak seemed to be coming from the trunk, this leak appeared to be in front of the rear wheel.  This made me think I had a problem with either an hydraulic line to the right hand top hydraulic cylinder, or the cylinder, itself.  There is only one way to find out.  <br />
<br />
The convertible top system on the XJS is much simpler than the nightmare installed on the XK8.  Even so, the lines and cylinders are located near the rear quarter windows, which means the back seat and quarter trim panels need to be removed to access the cylinders.  <br />
<br />
Today seemed like a good day have a look at it.  Time to break out some tools.

    A few months ago, I tried to lower the roof on the XJS. The first clue I received that something was wrong came in the form of a strange noise from the convertible top pump motor. It made a noise that seemed to suggest the system was low on fluid. But the roof lowered the way it was supposed to do, and I didn't give the matter a second thought.

    That is UNTIL I saw a trail of red fluid under the right side of the car after I pulled out of the garage. So I've got a leak somewhere. But unlike the incident with the XK8 last year where leak seemed to be coming from the trunk, this leak appeared to be in front of the rear wheel. This made me think I had a problem with either an hydraulic line to the right hand top hydraulic cylinder, or the cylinder, itself. There is only one way to find out.

    The convertible top system on the XJS is much simpler than the nightmare installed on the XK8. Even so, the lines and cylinders are located near the rear quarter windows, which means the back seat and quarter trim panels need to be removed to access the cylinders.

    Today seemed like a good day have a look at it. Time to break out some tools.

  • The rear seat cushion is held in place by two Philips head screws and washers.

    The rear seat cushion is held in place by two Philips head screws and washers.

  • With the fasteners removed, I lifted upward on the cushion and pulled it out of the car.

    With the fasteners removed, I lifted upward on the cushion and pulled it out of the car.

  • The rear seat backrest is also held in place by two Philips head screws.

    The rear seat backrest is also held in place by two Philips head screws.

  • With those fasteners removed, I lifted upward on the backrest and removed it as well.

    With those fasteners removed, I lifted upward on the backrest and removed it as well.

  • The rear quarter interior trim panels are held in place by several push-pin retainers.  The panel is removed using a trim tool and prying the push-pins loose from the body.

    The rear quarter interior trim panels are held in place by several push-pin retainers. The panel is removed using a trim tool and prying the push-pins loose from the body.

  • With the trim panel removed, I also have access to the rear speaker.  I noticed a speaker problem a few months before the roof issue surfaced.  No matter what music source I would use, (CD, USB, or radio), it sounded awful.  So as long as I was in the neighborhood, I decided to replace them as well.  The speakers are accessed by prying the plastic retainers away from the speaker carrier with a trim tool.

    With the trim panel removed, I also have access to the rear speaker. I noticed a speaker problem a few months before the roof issue surfaced. No matter what music source I would use, (CD, USB, or radio), it sounded awful. So as long as I was in the neighborhood, I decided to replace them as well. The speakers are accessed by prying the plastic retainers away from the speaker carrier with a trim tool.

  • Even though the stereo was upgraded before I bought the car, the rear speakers are the original Jaguar OEM pieces.  Looking at the back of the speaker, you can't tell anything is wrong.

    Even though the stereo was upgraded before I bought the car, the rear speakers are the original Jaguar OEM pieces. Looking at the back of the speaker, you can't tell anything is wrong.

  • Looking at the front of the speaker revealed the problem.  The paper-like material has disintegrated after 22 years.  Both rear speakers need to be replaced.

    Looking at the front of the speaker revealed the problem. The paper-like material has disintegrated after 22 years. Both rear speakers need to be replaced.

  • With the trim panel out of the way, I had easy access to the top cylinder and lines.

    With the trim panel out of the way, I had easy access to the top cylinder and lines.

  • The outside of the right side cylinder was coated with fluid residue.  But I saw no evidence of a leak from the lines.

    The outside of the right side cylinder was coated with fluid residue. But I saw no evidence of a leak from the lines.

  • The only way to test the system is to add fluid to the pump reservoir and see what happens.  When I pushed the roof switch, fluid poured out of the top of the cylinder.

    The only way to test the system is to add fluid to the pump reservoir and see what happens. When I pushed the roof switch, fluid poured out of the top of the cylinder.

  • It looks like the upper seal on the hydraulic cylinder has failed.

    It looks like the upper seal on the hydraulic cylinder has failed.

  • The upper seal has disintegrated and is completely gone.  So the pump motor was pumping fluid straight out of the top of the cylinder.

    The upper seal has disintegrated and is completely gone. So the pump motor was pumping fluid straight out of the top of the cylinder.

  • The fluid then ran down the body of the cylinder and into the car body eventually leaking out onto the floor.

    The fluid then ran down the body of the cylinder and into the car body eventually leaking out onto the floor.

  • The parts order for this project wasn't actually too painful.  The rear speakers were surprisingly still available and cost a mere $11 each.

    The parts order for this project wasn't actually too painful. The rear speakers were surprisingly still available and cost a mere $11 each.

  • I couldn't help but notice the "old looking" tape on the side of the speaker boxes.

    I couldn't help but notice the "old looking" tape on the side of the speaker boxes.

  • I wonder how long these have been sitting on the shelf.  But I'll be happy as long as they work.

    I wonder how long these have been sitting on the shelf. But I'll be happy as long as they work.

  • I removed the remaining plastic fasteners with my trim tool and removed the speaker carrier from the trim panel.

    I removed the remaining plastic fasteners with my trim tool and removed the speaker carrier from the trim panel.

  • The speaker is bolted to the plastic speaker carrier in three places.

    The speaker is bolted to the plastic speaker carrier in three places.

  • I bolted the speaker in place and reinstalled the speaker carrier.  The edge on a couple of the plastic fasteners broke.  But they snapped back into place and will work fine.

    I bolted the speaker in place and reinstalled the speaker carrier. The edge on a couple of the plastic fasteners broke. But they snapped back into place and will work fine.

  • The left rear speaker looked the same as the other one.  The paper-like material was gone.

    The left rear speaker looked the same as the other one. The paper-like material was gone.

  • I bolted the new left rear speaker into place.

    I bolted the new left rear speaker into place.

  • Now it was time to replace the top hydraulic cylinders.  Like the rear speakers, the top cylinders were also original to the car.  In this case, it's always a good idea to replace both cylinders, (if one 22-year-old cylinder failed, the other one may not be too far behind).  The OEM units are obsolete from Jaguar.  Thankfully, reproduction units are readily available, (and much less expensive) in the aftermarket.

    Now it was time to replace the top hydraulic cylinders. Like the rear speakers, the top cylinders were also original to the car. In this case, it's always a good idea to replace both cylinders, (if one 22-year-old cylinder failed, the other one may not be too far behind). The OEM units are obsolete from Jaguar. Thankfully, reproduction units are readily available, (and much less expensive) in the aftermarket.

  • Replacing the cylinders was a surprisingly simple repair.  The first step was to remove the top mounting bracket.

    Replacing the cylinders was a surprisingly simple repair. The first step was to remove the top mounting bracket.

  • The top cylinder pivots around this bracket.

    The top cylinder pivots around this bracket.

  • Two bolts hold the bracket in place.

    Two bolts hold the bracket in place.

  • With the bracket out of the way, the locking pin that holds the cylinder rod to the top frame can be removed.

    With the bracket out of the way, the locking pin that holds the cylinder rod to the top frame can be removed.

  • I released the clip and removed the locking pin.

    I released the clip and removed the locking pin.

  • With the upper and lower hydraulic lines disconnected, the top cylinder slides off of the mounting bracket.

    With the upper and lower hydraulic lines disconnected, the top cylinder slides off of the mounting bracket.

  • Installing the new cylinder was a simple matter of connecting the lines, reinstalling the rod locking pin, and reinstalling the mounting bracket.

    Installing the new cylinder was a simple matter of connecting the lines, reinstalling the rod locking pin, and reinstalling the mounting bracket.

  • With the right side done, I repeated the process for the left rear cylinder.

    With the right side done, I repeated the process for the left rear cylinder.

  • With the new cylinders in place, the final step in the repair was to fill the top reservoir (located in the trunk above the battery), and bleed the system.  <br />
<br />
It's not uncommon for convertible top hydraulic systems to use something like automatic transmission fluid.  This system, however, calls for "Univis J13" hydraulic oil which, like the top cylinders, is obsolete from Jaguar.  Hydraulic oils vary quite a bit in terms of viscosity.  Using a thicker fluid can cause damage to the pump mechanism.  It took some searching according to the original specification.  But I found a replacement fluid:  MIL-H-5606-A, a military grade "super clean" hydraulic oil used for aviation applications.  Like the rear speakers, this fluid is available at a very reasonable cost, (I paid $9 for a quart).

    With the new cylinders in place, the final step in the repair was to fill the top reservoir (located in the trunk above the battery), and bleed the system.

    It's not uncommon for convertible top hydraulic systems to use something like automatic transmission fluid. This system, however, calls for "Univis J13" hydraulic oil which, like the top cylinders, is obsolete from Jaguar. Hydraulic oils vary quite a bit in terms of viscosity. Using a thicker fluid can cause damage to the pump mechanism. It took some searching according to the original specification. But I found a replacement fluid: MIL-H-5606-A, a military grade "super clean" hydraulic oil used for aviation applications. Like the rear speakers, this fluid is available at a very reasonable cost, (I paid $9 for a quart).

  • I filled the reservoir and cycled the system several times, topping off the fluid level with each cycle.  After a few cycles, the roof raised and lowered quietly and quickly like it was originally designed to do.

    I filled the reservoir and cycled the system several times, topping off the fluid level with each cycle. After a few cycles, the roof raised and lowered quietly and quickly like it was originally designed to do.

  • I cycled the system a few more times to make sure nothing was leaking before cleaning and reassembling the trim panels and seat.  All I have to do is clean the car up, and I'll be ready for the 2018 show season.

    I cycled the system a few more times to make sure nothing was leaking before cleaning and reassembling the trim panels and seat. All I have to do is clean the car up, and I'll be ready for the 2018 show season.

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