Hi all, 1st post here!

I have bought my dad an early convertible for his 60th, but it has since developed some porblems that I'd like to solve myself.

The hood pump has since stopped responding to the switch- no idea why.

I have tested the 12v supply to the motor and that is all good- the relay is clicking away nicely too, but the pump is not responding.

The fluid level looks okayish- little bit low (on low marker) and I haven't seen any trace of leakage, so am suspecting it is an internal failure on the pump motor.

Can these be stripped for further testing- do they have any internal safety mechanisms that would stop the pump from priming??

Also, while it's being worked on, I may as well take the steps to flush the fluid (last time it was done (invoiced) was 2011) so any ideas on the steps to take would be great!

Any help would be greatly received!

 

I've had another look tonight, I disconnected the negative terminal from the battery for 10mins in the hope that if the control module was confused it would reset.

It has made no difference. So what now?

Rear quaters drop, front windows drop a tad but no response from the pump- It definitely has a 12v supply to the pump when commanded on the switch (black and white wires with the white multi plug).

 

Have you actually checked for 12v at the pump leads with a meter? If no 12v there I'd try another relay. If there is 12v at the pump then disconnect the pump leads and check the motor resistance. If it is open circuit then the motor is bad or there is a bad connection somewhere.

Dave

 

I can't lay my hands on my multi meter to check continuity of the motor windings, but when I do, do you happen to know the resistance perameters?

http://jagrepair.com/images/TSB/XK8/501-11am.pdf

I had a read of this TSB and tried to time the main control switch out, which has just confused the front windows- when you press the switch now the rear quaters drop nicely, but the fronts jump up and down. Perhaps this is because they haven't learnt there position from the battery disconnect... I don't know.

It'll have to wait for another night when I have a meter to hand.

 

Make sure the petcock on the pump in turned fully clockwise.

Also check the 40 amp fuse in the boot fusebox.

 

petcock is turned in the automatic position and 40A fuse is good.

 

Do you have a 'Hood not latched ' message on the display?

 

The door windows need to be reset. Press up and hold until you hear click, press down until you hear click, just a couple of seconds.

 

When we put the roof down manually it had an error message on the dash- hood latch failure, but this disappeared when we raised the roof.

 

Not sure what the DC resistance of that motor should be but if its shorted it should blow the fuse and if its open it will just not do anything. It could also still be the relay. Just because it clicks doesn't mean the contacts aren't buggered.



Dave

 

We want to see ~ 0.5 ohms as the DC resistance of the motor. And open-circuit from either of the pins on the power connector to the pump body.

 

I'll have a look in the morning, thanks for the info so far!

So am I right in thinking that if there is a switched live to the pump (granted I don't know the voltage) that all the microswitches/sensors are working correctly, and the hood folds nice & freely manually that the only problem can now be the pump?

Are there any other internal safety cut-offs or things that can stop it from functioning?

Fluid level is roughly on the low marker, maybe just a smidge below as the car is parked on a slope. Can this stop it from working?

 

Yes it can, and is quite sensitive to having the correct level. You should top it up. Get a litre of Pentosin CHF-11S.

I would also run it manually through a full cycle again if the fluid alone does not work (taking down the top latch manually this time). It is possible for the electronic controller to get confused as to what state the mechanism is in.

 

Is it that the pump stopped running or is it that the pump is running but not producing Hyd pressure?

 

The pump does not run at all.

 

I don't know if it is related to your problem, but the Driver's Handbook cautions against manually lowering the top:

"Caution: Do not attempt to open the convertible top manually, as damage to the linkage mechanism may occur. If necessary, the convertible top can be closed manually..."

http://www.mediafire.com/download/xt...19m/USA+06.pdf
pg 3-25

 

I just manually cycled the top of the XKR I'm working on twice yesterday. As long as the hinge releases easily and you don't force it there is no problem. But it's important to open and close the latch in the proper sequence order.

 

Two comments:

In 6 years of screwing with the hydraulic systems on two car I do not remember any posted information on a pump motor actually failing although several have been replaced.

The DC pump motor turns in both direction under control of the relays, micro switches and body control module. That means that one lead is positive and the other ground for one operation and switches for the reverse operation.

Point being that the pump is the very last thing to replace.

From a historical perspective the micro switch on top of the right ram is the most likely problem followed by the switches at the latch.

 

The security module controls the pump with input from the micro switches. At this point I would open the roof and park the latch and then do a hard reset reconnect the battery check the fluid level and the petcock closed then press the closed button and hold it. Let us know what takes place. Also have the engine running when testing.

Gus
WWW.jagrepair.com

 

I guess that would rule out one of the relays, worth a shot.

I won't be able to test this until Friday- he's taken the car away for a few days on holiday already!