last year I had a problem with drivers seat back not working I fixed and wanted to share with members
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DRIVERS SEAT - LS 400 (1990) We call it “the Dream Machine”
I wanted to share with members of LOC the answer to a frustrating problem I recently encountered in the hope others can resolve the same problem should it happen on your “dream Machine”
While cleaning the roof with another coat of car polish I was standing on the driver’s door sill and inadvertently must have touched recline button on the side of drivers seat leaving the seat in fully reclined position.
When trying to return the seatback to normal driving position the seat twisted, and stopped short of normal, because the LEFT side of the seat was not moving.
I searched both the UK & US LOC forums and found that others had encountered similar problems; in my case I was NOT able to drive the car.
The solution from members was to locate the Aluminium Tube (with black plastic cover) located at the base of seatback this is visible if you look at the junction of seat & seat back near the hinge.
How seat recline works:
The way the recline feature operates is by an electric Motor on right side of seat as you look at windscreen, from this there is a tapered metal spline, and the aluminium tube is ridged inside the tube and slides over the spline by this method the tube connects in the same way to the LEFT side and drives at the same speed as the RIGHT side.
The Problem is:
In my case the LEFT side of the aluminium tube had been cleaned of its ridges (rather like a pencil sharpener) so no drive connection possible to LEFT side of seat.
The solution many LOC members had suggested was GLUE it with Araldite type of glue and let it cure for 12hours or more, I did this twice with ZERO success…
How to Fix:
You will need to remove the seat from the car; there are 4 x 14mm bolts,
•slide seat forward remove 2 rear bolts,
•move seat backwards remove 2 x forward bolts
•You will need lift off carpet covered plastic covers, to find bolts
•Disconnect wiring harness
•Remove seat via rear door
•Remove plastic panel on back seat (2 small Phillips screws at bottom of plastic backing) pull sides of plastic cover off clips on seat frame and slide down to release 2 x clips that go under top of seat frame.
•Free up leather from base of seat back by removing wire loops from wire frame section that attach leather also remove 6 x steel clips (3 each side) so you can release leather and foam filler away from lower seatback frame. (leave seat cushion leather in place)
You can now see the aluminium tube covered in black plastic tube. To release this tube, you need to remove 4 x bolts (2 from each side) of hinge arm that connects to seat back to hinge arms. When removed you will be able to push seat hinges apart just enough to remove the aluminium tube from the steel splines.
NEW ALUMINIUM TUBE:
My friendly local garage called Lexus spares department at main dealer and they faxed over exploded drawing of Drivers seat, (ref: MN 2071-A) the aluminium tube was identified as Lexus part number is: 72501D
My garage called and ordered the part which was available in 3 days at a cost of £11.08 + vat.
I inserted new tube, and put everything back together and all works normally. (Interesting to note that the new part is slightly longer than original which ensures tube does not move from side to side, which is my guess why the problem happened in the first place.
IMPORTANT:
Be sure the seatback is straight (not twisted, be sure both sides of seat are level) when installing the new part, otherwise the seat will twist when electric motor runs, and seat may not return to correct position.
IAN LORD
Membership number: 10742
Location: Bournemouth