1st off...I didn't do "comprehensive pics"...mostly because I did the entire fitting myself, and not really having any idea how long the task would take, I got stuck in and went at it. So, apologies for the omission.
To the description:-
I had the use of a service pit, and to anyone who wants to make this conversion, I cannot emphasise the usefulness of such a facility. I doubt the task would have been as comfortable or straightforward without being able to work under the car with relative ease.
I firstly removed the rear section of the exhaust, and having a full M zed type exhaust it meant disengaging the front box and the two rear boxes. This took me about a hour, mostly because I was working entirely alone, and also because I should really have made use of some rubber grease to ease the removal of the "8" shaped rubber mountings ( I think I have about 6 of them under there) I did use rubber grease when re-fitting though, and had the help of another pair of hands at that time...rubber grease is a
must have for this type of job.
The next item to remove was the rear stabiliser bar...a very simple task, 13 socket and a ratchet...10 mins.
Next up was to remove the single ear bolt in the OEM cover. I placed a small hydralic jack under the diff, and it was stood on a steel frame which spans the service pit side walls. I raised the jack until it took the pressure off the bolt, and undid it (19 socket / ratchet, and 19 ring spanner on the nut side). 10 mins to set up the jack and remove the bolt.
Once the bolt was out, I lowered the jack until the diff was clear of the metal brackets which sandwhich the ear of the OEM diff, and using a "baby" angle grinder, cut away the rearmost flap of the bracket level with the subframe cross member.
I then turned my attention to the opposite side and had to simalarly cut away the hanging bracket of the spare wheel aahinge attachment point. This is a boxlike structure and a PITA to get at with the rear drive axle still attached to the diff. Perhaps in retrospect I should have simply removed the axle at the diff and allowed myself comfortable access on both sides,. However, since I wasn't yet 10% sure about my new bracket being an accurate fabrication, I felt that I wanted to restrict the movement of the diff laterally, so left them in place.
I then drained the diff oil and removed the OEM diff cover, and covered the exposed diff interior with a thick piece of cloth to keep any dust etc out of there, and cut off the forwardmost diff bracket flap level with the cross member. This process took around 30 mins, mostly as I said, due to restricted access by the axles.
I then changed the cutting wheel for a grinding wheel and ground down the section of the OEM bracket which is welded to the rearward side of the subframe. (Because of my bracket design, the welded remains on the opposite side of the subframe can remain ) The metal of this bracket is aprox 2mm thick, and is spot welded across the underside of the cross member in 10 places over a relatively small area of around 75mm x 120mm...another really filthy, noisy and because of sparks, sometimes hot, painful and smelly aspect. This grinding bit took aprox 30 mins...with a couple of breaks to rest from working with a fairly hot, heavy tool above my head...also the angle grinder needed cooling.
Once all the remnants of the OEM bracket was ground away, and finished flush to the subframe cross member, Iused compressed air to blow away all the filings etc to clean the area. I then fiteed the aluminium "inter- gasket" and the new dual eared rear diff cover. I used only 4 bolts of the total 8 to hold it in position and tightened them to around 10nm (that is not very tight, but enough to hold the parts firmly enough).
I then slid my new bracket into positionand fitted the 2x M12 bolts through the brackets and the 2 ears of the cover and tightened them "firmly". I then used the small hydraulic jack to raise the diff until the new bracket came into contact with the subframe cross member, and was held ther under "mild" upward pressure. I used a sharp tool and outlined the edge of the new bracket where it made contact with the crossmember, and then lowered the jack again. I then used the angle grinde fitted with a sanding flappy disc thing to remove all the paint either side of the outline mark on the crossmember. This so that when it came time to weld, the metal would be clean and provide the strongest weld.
Once complete, I used compressed air to blow all the dust away again and clean the work / welding area. I then raised the diff until the new bracket was up comfortably under the crossmember, and then it was the turn of Quinton to do his stuff. I can weld, but he is a pro. He "tagged" the new bracket to the crossmember in 4 spots, and then I removed the 2 x 12mm ear mount bolts, dropped the diff down again, and removed the diff cover, covering th exposed works with the cloth again.
At this point I must suggest that it would be best to have both axles disengaged from the diff. It allows clear access to all the areas that require welding. It can be done without removing them, but not easily. Also, it's best to be able to ensure good clean continuos welds to remove them....Removal time 30 mins. Replacement is aprox the same time
Once Quinton had done his welding - 20 MINS - it was time to do the final fitment of the new rear cover. This requires 2 x papaer gaskets - one either side of the aluminium "inter-gasket". I used Locktite Grey high tem gasket maker. The diff face, the cover face and both sides of the intergasket was coated with the loctite, the paper gaskets were "stuck" to the intergasket, and then the cover & inter-gasket fitted to the diff and all 8 bolts inserted and torqued to 40nm. The sequence of tightening these bolts is essentially a process of diagonal movement from one bolt to it's diagonal opposite. I first took them all to 20nm, then 30nm and finally to 40nm. I filled the diff with oil and after final fitment topped up. Then the diff was raised by jacking up until the diff ears aligned with the bracket ear holes, and the 2 x 12mm bolts with washers either side were inserted, and tightened to 60nm and using self-lock nuts. time - 25 mins. The axles were re-fitted to the diff and torqued.
The new bracket was painted with black Hammerite 10mins. A welcome tea break followed to allow the Hammerite some drying time -20 mins...
The rear, stabiliser bar was replaced. 10 mins, the speed sensor jack pluged into the sensor on the rear of the diff, and the exhaust re-fitted. - 20 mins.
Job completed. Aprox 2hrs 10 mins.
You will be able to see the edges of the 2 paper gaskets either side of the aluminium inter-gasket. The inter-gasket is necessary because of the bladed disc inside the diff which spins off the right axle output. It passes between two magnetic arms of the sensor, and thereby generates an induced electrical pulse. The position of the sensor on the dual ear cover is aprox 8mm deeper into the diff, and consequently the blades will not pass through the 2 magnetic arms, so to remedy this I have had made the aluminium inter gasket which once it's two mating faces have been machined is 9.5mm thick. This allows the bladed disc to pass comfortably between the sensor arms. If you scroll back up into this post you will see pics of the sensor position on the dual ear cover vs the OEM cover.
Here is a pic of the bladed disc which passes through the sensor arms.
My observations after the fact:- It's a relatively easy conversion. It's messy and uncomfortable even with the benefit of a service pit and would probably take an hour longer without the pit. The tools required are basic. I'm very pleased with the final result, and all that now remains is to fit / weld in the metal re-inforcements into the boot to re-attach the boot floor to the crossmember below.
The pic shows these metal parts which I had laser cut complete with 8mm holes which line up with the existing spotwelds. These will be drilled out, and with the metal bits appropriately positioned, welded throught the holes, and then seam welded around the edges to complete everything.
Comments, questions and criticisms welcome.
Monday the bracket will be taken to be welded into a complete product. Also, a pic of the aluminium gasket which has now had both faces machined. It will fit between the diff and the diff cover and provide for the speed sensor bladed wheel to pass comfortably between the 2 arms of the sensor.
