Kerbside Motors

Audi ur-quattro - Seat Repair

The Hawg Ring Lunge

Many ur-quattros that we see have collapsed side bolsters in the driver's seat (look for foam crumbs underneath) and/or failed seat heaters.

The seats are very easy to remove - a 5mm Allen screw and a 10mm nut secure the front of the slider and two screws secure plastic bits at the rear of the runners. Put some newspaper in the rear footwell so you don't get grease on the carpet. Don't forget to unplug the heater cable and, on a WR, the driver's side seatbelt warning switch.

Once on the bench, check the plastic side panels in good light. Each side is secured by three little dowels pushed into expanding clips. When these dowels are removed, the panels just pull off. Make a careful note of the wire locations in the heater plug, and undo it to release the wires. Remove the rake adjustment knob - it's held on by three tongues and you can reach inside the back of it with a hook and pull them off one by one. Once it's off, remove the adjustment mechanism. The back is held to the base by two clevis pin type fittings with push-in clips - just pull them off and stretch the arms out over the pins. The seat should now be in two pieces.

If you're just repairing the heater element, check the backrest and base for continuity. The elements are wired in series, and a break in either will stop both from working. Some people have successfully repaired breaks by soldering, but it's tricky as the elements are a silver alloy and ordinary solder doesn't work very well.

Remove the seat cover you're interested in. This will usually be the base. You'll need good side cutters (not the sort you find in 104-part tool kits for under a tenner at Argos) to cut the hog rings that secure the cover to the steel wires passed through the cushions. More of this later. Count the rings you cut and clear out all the fragments. If the side bolsters had collapsed, you'll need a new seat squab. The spare parts diagrams are very confusing; you need 855 881 361C for post-1984 cars - £63 + VAT. Earlier cars had multi-part squabs that are no longer available - the later part can be made to fit.

The replacement heater element - 443 963 555S, £98 + VAT - goes inside the seat cover. Don't be tempted just to lay it on the seat cushion underneath the cover - it will then be underneath a layer of foam in the seat cover and will hardly warm your bum at all.

Lay the cover out, surface facing down and lay the replacement element on top to get the orientation. Note that the wires should come up towards you - not down towards the seat cover surface. Otherwise you'll feel the lump when sitting on the seat. You can see that you'll have to cut two slits with a very sharp knife in the cloth backing of the seat cover to thread each arm of the element through - it comes out the other end and the tab is folded over. A ruler is ideal for pushing the element through.

You actually cut through the cloth backing and the thin foam layer - the element slides in right behind the old element, which stays in place. Don't even think about removing it. When you replace the seat element (as opposed to the backrest element) you still need the sensor in the old element. Cut the slits at 45 degrees - otherwise you'll get a small ridge in the seat when reassembled. If you're using a Stanley or Plasplugs knife, be aware that the foam will blunt the blade very quickly - have spare blades to hand. Trim off the old (now unused) supply wires to the seat base element, but be careful to leave the sensor wires intact.

You need two tools for stretching the seat cover back on. Don't be tempted to use cable ties - they're not designed to take intermittent loads and often give way after a year or two.

a) The Hook. This is made from a wire coathanger. Take a straightened piece and form the smallest hook you can in one end. Make a handle at the other. Don't throw this away after doing the job - it's ideal for replacing the spring clips on the air filter box and retrieving the hydraulic pump belt when you've dropped it down the front of the car.

b) The Pliers. We use Mark-Line 12108 - Snap-On YA808 is an alternative.

You also need a pack of hog rings - Audi's cheapest spare part. N 015 261 1 is around £10 for a pack of 100. If you have any problems getting the tools or the rings, try a specialist upholstery factor. Jim Haseltine reported good service from:

Put the cushion on the frame, and start stretching the cover over it. Remember where you cut off the old hog rings? As a check, you should put back the same number you cut out earlier. The replacement procedure is to load a ring into the pliers and hook the top of the 'C' shape into the seat cover wire. Then get the hook and pick up the wire embedded in the cushion. Then LUNGE - pull the cushion wire up, at the same time as pushing down with the pliers, and hook the cushion wire into the bottom of the hog ring 'C'. Then, with a silly smirk, just squeeze the pliers shut. Takes seconds with practice, and produces a really tight seat.

It's called "The Hawg Ring Lunge".