Earlier I posted I was interested in buying my neighbors 1992 Jaguar vanden plas. I did now I need to replace a broken alternator belt but I don't know how to release tention from the AC belt. I read how to do it but I don't understand what a pivot tension bolt is or where to find it I'm hoping someone can help maybe provide a pic of where there's is and describe in detail what I need to do.

 

Hi Donald,

The adjuster for the A/C compressor belt tension is part 3 in the diagram below. The threaded shaft of the adjuster slides through the lower hole in the adjustment sleeve, part 4, and the position of the shaft is secured by the two nuts numbered 6. The compressor's position is also secured by bolt number 14 and nut 16, which tighten onto the slotted stabilizing link or bracket, part 13. The compressor mounting bracket, part 1, pivots on the long bolt 7, which is tightened by nut 9.



To remove the compressor belt, if I recall correctly the procedure goes something like this:

1. Loosen but do not remove nut 16. You will probably have to put a wrench on the head of bolt 14 in order to sufficiently loosen the nut.

2. Loosen the right nut numbered 6, then thread the left nut 6 counter-clockwise so that it moves up the threaded shaft toward the eye on the end of the adjustment bolt 3.

3. If the compressor will not pivot to loosen the belt, you will need to also loosen nut 9, probably with a wrench on the head of bolt 7.

4. Thread nut 6 as far as you need to so the compressor can rotate enough for you to slip the belt off of the pulley.

5. Reassembly is the reverse of the above. The two nuts numbered 6 are tightened to hold the adjuster in place once the belt tension is correct, and the other nuts are then tightened to secure the compressor. Don't overtighten the belt or the compressor bearings may fail prematurely.

If none of this makes any sense now, I think it will once you get those fasteners loosened and see how the compressor pivots to loosen or tighten the belt.

EDIT: It just occurred to me that I may be remembering that some or all of these bolts & fasteners may not be metric, but rather SAE/Imperial (inch fractional). So if your metric wrench doesn't seem to fit properly, try an SAE/Imperial wrench instead.

Cheers,

Don

 

Thank you so much for that information I now have the AC belt off. Could you provide the same descriptive information on the serpentine belt?

 

Good work on the A/C belt. So the idea is the same for the main drive belt. The tensioner for the entire belt is at the alternator, which is on the left side of the engine (right side when facing the engine from the front of the car). Unfortunately, on U.S. cars the secondary air injection pump sits above the alternator, which makes access to the alternator mounts and belt adjuster more difficult than those on the A/C compressor. But the tensioner components are very similar, so you'll see what you have to do. I use the word "see" figuratively, since you may have to do some of this loosening by feel. An inspection mirror and good light will help you get a look at the parts you have to loosen.

Below is the diagram of the alternator mounts. Part 11 is the belt tensioner, secured by the nuts 14 (only one of the two nuts is numbered in the diagram but the other one is below the lock washer 13). Loosen the top nut, then thread the lower nut down the shaft toward the eye of the adjuster. In order to get the alternator to pivot so you can remove the belt, you will probably also have to loosen the nut 8 a little while holding another wrench on the head of the pivot bolt 2. You may also find that it helps to loosen screw 10 a little so the adjuster sleeve 9 can pivot more freely to slide down the adjuster shaft, and loosen the bolt or screw that passes through the eye of the adjuster (not shown) so the adjuster can pivot freely.




Cheers,

Don

 

I have replaced the belts all 3 AC alternator and airpump I completely removed the airpump to replace the alternator belt then replace the air pump I put the car on the ground now it won't start during the whole service I never remover any electrical outlets accept the air pump it was starting before now it won't any ideas

 

The Crankshaft Position Sensor (CPS) is in the vicinity of the belts - Is it possible you disturbed it when you changed the belts? If the CPS is disconnected, the engine won't fire.

A quick way to see if it's ok and working is to look at the rev counter when cranking the engine. The rev counter should indicate about 200 rpm.

Larry

 

It does read around 200rpm but won't turn over oil reads 0but I checked the dipstick and it seems good maybe more than good battery is 13 but as it cranks it drops to 9 brand new battery I just bought yesterday I'll check for a spark in the morning but I just can't believe I haven't even driven it once and it won't starti think this dream car is gonna be expensive

 

It's probably something very simple. For example, if the battery voltage falls below something like 10.4 volts while cranking, the Engine Control Module (ECM) will not trigger the ignition to fire, so my first guess is that your new battery has not had time to receive a full charge after sitting on the shelf in the store for who knows how many months. If you have a battery charger, give the battery a good charge and try again.

You can also check the connections at the ignition coil and ignition amplifier, which sits right below the coil, and check the king lead between the coil and the distributor.

And I assume the connectors at the alternator were not disturbed?

Please keep us informed.

Cheers,

Don

 

Went outside this morning to listen for fuel pump and check from spark and it started right updo you have any idea what caused it not to start yesterday