1991 BMW 850i
page 7
Strong Strut
I picked up this Strong Strut new in the box from a local E31 owner. Installation turned out to be a lot more painful than I was expecting ...
The problem is the drivers side mounting bracket leaves insufficient room for the wiring harness that runs along side it. I ended up unwrapping my wiring harness so I could re-shape it to fit down the narrow clearance that remains. I also had to trim back the plastic cover so it would fit and deform the metal cage around the fuse box to make a little more room. In my opinion the design should have been thought through a little more carefully especially for the $450 or so these sell for. Aside from this issue the unit fits beautifully and is nicely finished.
New front seats
5/13/16
I finally got around to installing the new front seats today.... they came form a car with only 65K mi and are in beautiful condiiton.
Removing the seats from the car was easier than I expected. I removed the trim panel with the seat controls and the switch assemblies as they stick out and would be easily broken. To remove, tilt the seats fully forward and lift out (2 persons).
The new seats are in great condition and everything works (the seat rails on my original seats were both messed up). These seats came out of a car with only 65K mi and show very little wear!
I dismantled the seat rail of my old drivers side seat...
The lead screws below move the seat forwards and backwards. To remove them you pull the seat cables out (they are a simple push fit) undo the 3 x torx screws in the side of the seat rail (good idea to heat these up before trying to remove them), a Phillips screw on the end) and a couple of torx screws on the other end. Then the assy shown below can be slipped out the seat rail.
You can see the lower nylon gear is cracked in a couple of places and was simply spinning on the end of the lead screw.
Rear axle/suspension refurb (Feb 2023)
Several years ago I purchased a complete rear sub-frame from a car with only 65K mi. It was already off the car when I got it. Part of the sub-frame was damaged so I could not use it but most of the attached parts were in excellent condition. The pictures below are a combination of the parts removed from the spare sub-frame and the parts off my car with 133K mi. I'm using the best of both with many new parts too!
I dropped the rear sub-frame to refresh everything including the 4 sub-frame mounting bushings. Most of the bushings and wheel bearings were replaced and some of the control arms replaced with brand new parts...
First job was to mark the eccentric bolts (camber and toe) so they can be put back in about the same positions.
I loosened all the bolts and took plenty of pics for reference when putting things back together!
Don't loose the small pin for the handbrake cable.
I removed all the control arms on the car before dropping the sub-frame (others prefer to drop the whole thing in one piece).
Differential and subframe removed...
Removing the hubs is pretty straight forward... I removed the hub and half shafts as one assembly.
Separating the half shafts can be a real pain as the splines are usually a very tight fit. The tool below makes the job easy and also supports pulling the shaft back into the hub (see later).
Next step is to pull the wheel hub off. I used an OTC slide hammer for that.
A few good pulls on the hammer and the wheel hub starts to come out. I could keep hammering away and eventually pop it off but at this stage it is much easier to...
install a large bearing separator (Harbor Freight) and run a few wheel lugs down to extract it.
As expected, part of the wheel bearing remains on the wheel hub.
Then removed the dust shield and the large snap ring that holds the wheel bearing in place.
Pressed out the wheel bearing. My shop press makes this job very easy. You can see the condition of the hub mounted ball joints in these pics
Here's one of the wheel carriers with the wheel bearing removed.
To remove the bearing inner race from the wheel hub I used a dremel to make 2 cuts opposite each other.
Cut as deep as you can without cutting through into the wheel hub then use a chisel to split the bearing (bearing metal is brittle and breaks easily)
With the chisel wedged in the bearing, slide it off. If you do it right there will be no damage to the wheel hub!
To press the larger ball joint (43mm dia) from the wheel carrier I used the inner race from one of the removed wheel bearings as the receiver and a 1=1/4" x 2" pipe nipple (from Home Depot).
I wrapped the pipe nipple in a couple layers of masking tape to prevent it scratching the sides of the wheel carrier when pressing the ball joint.
Inner wheel bearing race as the receiver, pipe nipple as the press. I used one of my bearing tools on top of the pipe nipple and it pressed out easily.
For the smaller ball joint I used a 30mm STANLEY 12pt socket as the press and my old wheel bearing inner race as the receiver.
Here is the rear hub with both ball-joints and the wheel bearing removed ready to begin rebuilding.
I used my E39 ball joint tool to press in the new ball joints. The cup on the left has the inner race from a 6207 bearing (about $6 on Ebay) inside it. The center bore on this bearing race fits nicely around the ball joint. Total investment so far to press and install the ball joints about $20 (6207 bearing, 29mm 12pt socket, 1-1/4'x2" pipe nipple, inner race from old wheel bearing).
New FAG rear wheel bearing pressed in (orange side out) and retaining circlip installed. Remember to install the disc dust shield before pressing on the hub!!!
Pressing on the hub
Pulling the half shaft back into the hub (with special tool)
One side finished! Half shafts are from a car with 65K mi and feel nice an tight (my originals with 133K have noticeable play), new ball joints and wheel bearing in the hub. Everything cleaned and ready to bolt back up to the car!
Ball joints in the lower arms were pressed out on the hydraulic press. New ones were pressed in with my E39 Ball joint tool... partway. I did so because this tool does a good job lining up the ball joint squarely when starting to press it in.
Once pressed in part way, I used my hydraulic press to get it to the required depth... this ball joint is positioned so it protrudes an equal amount on both sides. I eyeball'd it at first then used calipers to get it to exactly the right depth.
I sanded the arms down prior to pressing in the new ball joints (they had some light surface rust in a few places)
After installing the ball joints I gave them a coat of Rustoleum black gloss (brush on enamel).
And after that, noting that the original parts have a rubberized coating on the lower half, I gave the lower halves a coat of rubberized undercoating.
This is one of the rear upper control arms. The ball joints for these are not available separately from BMW, you have to buy the complete arm for $475 ea! I got some replacement ball joints from a seller on Ebay for a little over $100 ea (from Germany). Took the pic below after I had pressed out the ball joint so this actually shows the old joint about to be pressed back in. I used an impact socket to press the old bushing out (it buggers it up but not a problem since its going in the trash).
When pressing in the new ball joint be sure to press in from the side with a small taper. Heat the arm and freeze the ball joint prior to installation. Press the ball joint mid way through the arm (ball joint body is 24mm wide and the arm 40mm wide so recessed ~8mm on each side). Use a short piece of 1.5" exhaust pipe to press in. I used an impact socket to press it out but this destroys the joint and protective boot so cannot be used to press the new one back in. FYI... 1.5" exhaust tubing collapsed when I tried to use it to remove the old ball joint.
Here are the new bushings as received
I used a piece of 1.5" OD exhaust to press in the new bushings (purchased from Pep Boys).
I cut it into 2 pieces. Both are a snug fit around the boot on on each end of the bushing. The lower piece is important and limits the depth to which the bushing can be pressed in (you'll never get it exactly centered without this). The receiver is on the right, a piece of thick walled aluminum tube I happened to have lying around.
Here's the stack up ready for the press.
Pressing the new bushings in.
And here's the finished result, 2 x as good as new rear upper control arms.
What I didn't realize at the time was the holes in these ball joints were slightly undersized and my bolts would not fit through them (a bit dissapointing)! I had to ream them out slightly. These ball joints appear to have been a close size to the original parts that were machined down in outside dia slightly and spacers pressed into each end to match the original hole dia and width.
The rear subframe had some light rust on it so it was sanded down and re-painted. And then I replaced the 4 x subframe bushings.
Here's how I pressed out the subframe bushings....
First, with a hacksaw, carefully trim off the notched sides of the bushing so the subframe can be supported when pressing out the bushing from other side.
Trim off the rubber ribs on both ends of the bushing.
I used an small drill press vise to support the subframe and a round tube to press out the bushing. The subframe itself is supported on my transmission jack.
My vise doesn't have enough depth to receive the complete bushing so with it partially pressed out I cut off the lip with a hack saw and then able to use a large dia tube (kit of these with various sizes visible on floor in pic below) to support the subframe.
Pressing in the new bushings is a bit easier but you must first coat them with a temporary lubricant and be sure or orient them carefully. Don't even think of doing this without a lubricant... I tried a little dish soap and water and destroyed one of my new bushings... at $100 ea it was an expensive mistake!
I used this stuff which is available on Ebay and Amazon. One tube is enough for all 4 bushings ...
All 4 brand new bushings have been installed in the pic below.
Torque values for the re-assembly process...
Almost all back together now...
Transmission output flange seal
With the drive shaft removed you can see the transmission output flange is held in place with a large nut. On my car this nut was loose (a common problem I have heard)!
It looks clean in the pic below because this was after installing the new seal... It was an oily mess when I started!
Remove the nut and you can pull off the flange. Mine is in excellent shape (when running finger nail across glazed area I feel nothing).
There was a lot of crud build up in the splines...
I'm not sure if this is some sort of sealer... the service manual does not mention anything.
The leak at my real seal might actually have been down through the splines since the nut was loose. The splines are not a real tight fit... nothing like in the wheel hubs.
New seal has been pressed in.
Surfaces have been cleaned and a new output shaft seal installed.
Improvised holding tool to hold the flange in place while tightening the nut... worked great!
As you can see, the insulation above the transmission is completely trashed... It will be replaced when I get around to pulling the engine/transmission.
Rear Differential output flange seals
This was preventative maintenance... diff was not leaking.
The output flanges pop off easily with a pair of motorcycle tire irons. Other than some light glazing there was no perceptible wear on either flange.
I used a puller to pop out the seals (L and R).
The new seals have a different profile... I believe they are supposed to be an improved design. They come with a new 'C' clip which I also replaced.
The diff was thoroughly cleaned and given a fresh coat of paint (brush on Rustoleum).
Drive train alignment
First thing to note is that while the rear diff is centrally mounted in the car (both half shafts are the same length), the input shaft is offset 20mm to the passenger side.
The engine/transmission are centrally mounted.
The diagram below illustrates. For minimal vibration, the drive flanges must be exactly parallel to one another.... this means the diff points 20mm offset from the transmission.
The service manual describes how to ensure the transmission flange is centrally mounted in the car (there are 2 punch holes in the frame rails to measure to).
To check the differential flange to transmission flange alignment I mounted to laser pointer to a metal plate with holes drilled to mount it to either the diff flange or the transmission flange. The laser does not need to be exactly center mounted... to the extent it is off it will draw a circle when the shaft is rotated. The important thing is the setup must be rigid and not move as the shaft is rotated.
With the laser mounted to the diff flange and rotating the flange, I traced the circle at the transmission flange. You can see that it is pretty much central in the vertical plane and offset the right about 25mm in this pic. The diff input flange is offset 20mm so the pointing is off by 5mm to the right. I should point out that to line things up like this in the vertical plane I had to lift the front of the differential whilst tightening the mounting bolts for the front stabilizer arm.
To correct the 5mm offset the diff needs to be moved slightly. I accomplished this by moving the bushing in the stabilizer bar on front of the transmission very slightly. After that it was within a mm or 2 of 200mm offset and that was close enough for me.
I did the same thing with the laser mounted to the transmission flange, tracing the laser beam on the diff flange. I don't have a pic but it was about 22mm offset at the differential and in perfect alignment vertically. I tried loosening the front engine mounts and moving the front of the engine but it didnt seem to want to move and always settled into the same position. A 2mm pointing error is close enough for me so I left it.
Next up was adjusting the center support bearing...
Note that I had originally marked the location of the center support with some metallic spray paint. What looks like metal filings in the pic below is just paint specs... it freaked me out at first too!
Since the 2 drive flanges are in perfect alignment vertically the 2 halves of the drive shaft should be at exactly the same angle vertically... I used an electronic level to measure the angles and found I needed to drop the center support bearing 1/8" to achieve this. You can see the spacers I added in the above pic.
Adding keyless entry
I purchased this inexpensive setup on Ebay for about $15. The trunk release is not wired... just the door and trunk lock / unlock. It comes with a cabled flashing red LED (see pic below) but I didn't bother with it.
I installed it above the driver side footwell... above the GM module.
Here is the wiring diagram.
And here you can see how I installed it...
I did not wire up a siren yet but the pink wire is routed to the firewall and I will add later (under the driver side headlight is my plan).
For the splices I dismantled the connectors and removed the appropriate pin so I could slide heat-shrink back over the soldered splice (I didn't cut the wires).
It's not an easy place to work... I removed the knee bolster to gain better access (4 bolts).
And it works great!
Steering wheel swap
Replacing the stock steering wheel on these cars with a 3-spoke sport wheel is a popular upgrade...
I got this one from a seller in Germany for about $150 incl shipping. It's in pretty nice original condition.
After removing the original steering wheel you must remove the slip ring contact for the horn (bottom) and the pogo (top right).
They simply snap in place
Here's the back of the original steering wheel. Blue and brown wires are for the airbag.
And here's the back of my new steering wheel that must be modified.
Red and white wires are for the airbag; needed to solder the original airbag connector on to the wires.
Blue and brown are for the horn. Blue is connected the steering wheel metal core (ground) and brown is the horn. Orignal connector is cut off, blue wire goes no where since the core is grounded to the steering column. Original horn connector connect to brown wire.
Here it is ready to install...
For this wheel, the pogo pin that locks the slip ring in place is in a different position so I could not use it. Instead I simply tie wrapped the wiring harness to the plastic loop that secured the original horn slip ring contact (sorry no pic).
