F10: Rear Shock Absorber / Strut / Spring Replacement [GUIDE]

*Front strut-assembly replacement guide here - https://www.beemerlab.org/2017/09/f10-530d-front-shock-strut-spring-top.html*

Time to do the rear struts and springs on the 530d F10 this week as one damper has been leaking and while doing my tyres last week I noticed the spring has now broken at the bottom so this is now an urgent job. I picked up a pair of used complete struts (spring, damper and top-mount) from eBay for just £100. They are from another 530d and claim to be from a low mileage car. Well, they look a lot lower mileage than the ones I'm taking off lets put it that way and appear to be in pretty good condition. I get a lot of stick for constantly using second-hand genuine parts, but I still prefer this to buying new spurious parts where I can and have never had an issue!

GUIDE:

* This is not a difficult or time-consuming job, but will require a bit of brute force. *

1. First the rear seats need to come out. Lift the seat squab up at the front and detach it from the push-studs, press the seat-belt receivers through the recesses and lift the squab out. Next lift the seat-back upwards until it is free of the hooks at the top and lift that out, being careful of the door-sill paintwork and sliding it through the seat-belts. [You could always unbolt the seat-belts at the base using a T45-Torx socket to make this easier, but it's not essential].

2. The parcel-shelf now needs to come down in order to access the strut-top mount bolts in the shock-turrets. Remove the C-pillar trims by prizing out the plastic caps labelled 'Airbag' from the trim and removing the screw using a T25-Torx socket. Now carefully pull away the C-pillar trims and put to one side. Remove the five push-pin clips from the front edge of the parcel-shelf by levering the button in the centre upwards and pulling the plastic pin out. The studs can now be levered out. The parcel-shelf is now free to pull forwards and can be rested where the seat-back would be. [Remove the wiring-connectors to the speakers, but these should pop out by themselves anyway].

3. Lift the car and remove the corresponding wheel. [There is no need to be getting under the car for this job, so a jack and axle-stand is fine].

4a. The track-strut (pictured) needs to be moved out of the way to access the bottom strut bolt so first remove the plastic clips holding the E-brake wire-harness to the track-strut by levering them open at the bottom with a flathead-screwdriver and separating them from the strut. The wire-harness can be moved out of the way.

4b. Remove the bolt holding the inner end of the track-strut using an 18mm wrench. Pull the track-strut down and rotate it so it is pointing out of the wheel-arch. You now have plenty of room to get at the bottom strut bolt and lift the shock out.

5. Remove the bolt holding the bottom of the strut to the hub using a 21mm wrench.

6. Lift the triangle flap in the foam underneath where the parcel-shelf was to expose the studs to the strut-top mount and remove the three nuts using a 13mm wrench.

7. Wiggle the bottom of the strut free from the hub and the entire strut assembly is now free to be removed. It should be able to be lowered through the remaining suspension parts and to the rear of the car until it is free to be removed.

** IF YOU ARE CHANGING THE SPRING / TOP-MOUNT OR SWAPPING THESE ONTO A NEW STRUT THEN DO THIS NOW** [See this post for guide].

8. Make sure the new strut has the top-mount in line with the old one you removed by lying them next to each other and checking the bottom bolt-eyelet and triangle marking on the top-mount match up. [The triangle marking on the top-mount should face towards the back of the car with the bolt-eyelet facing the centre, or with the triangle marking facing you the bolt-eyelet should be pointing to the right for O/S (right-side) and left for N/S (left-side)].

9. Lift the new strut back up through the suspension and line it up into the strut-turret. [Triangle marking on top-mount facing rear of car] and screw the three 13mm nuts back on a few threads.

10. Lever the hub downwards until it meets the bolt-eyelet at the bottom of the strut meets its recess on the hub and screw the 21mm bolt back in about half-way.

11. Fully tighten the three 13mm nuts on the strut-top mount.

12. Fully tighten the 21mm bolt through the bottom of the strut.

13. Replace the track-strut / wheel as a reversal of steps 3 and 4.

14. If you are doing both sides then repeat steps 3 - 13 for the opposite side.

15. Replace the parcel-shelf, trim and rear seat as a reversal of steps 1 and 2.

E81 120d M-Sport: New springs and dampers!

Sean at work has a 1er with nearly 200k miles on the clock, through you would never tell as most of the parts have been replaced since he got it for a mere £700. Yes, you can get a zippy M-Sport 120d for this price, but unless you are willing to get your hands dirty I wouldn't recommend it. Of course, you probably are willing to do that or you wouldn't be here in the first place, so go sick there are bargains out there!

This time it's having new rear springs and dampers as one has leaked all of its fluid and is jammed in position. The opposite side was constantly hitting the bump-stop. She rides good now.

E60: PAS-Pump + Exhaust Vibration-Damper.

With everything else apparently working, the 530d was still of the road due to the niggling problem of an un-bleedable PAS-system and rattling exhaust.

• Bleed PAS-system with cap off reservoir and engine off, by turning the wheel lock to lock about 30 times and adding fluid until no more bubbles were coming out.
• Remove front-bumper and drive back onto ramps.
• Locate exhaust onto connecting-rods of vibration-damper.
• Modify connecting-rods to fit new exhaust position.
• Refit exhaust and reinforcement-plate.
• Refit engine centre-undertray.
• Drive off ramps, refit bumper and test drive!

PAS-Pump Bleed:

This is the hardest to bleed PAS-system I have ever come across, though the pipes / pump have been off the car for 3 weeks and could have allowed the system to drain and fill with air more than before. The pump was whining on tickover and making an almighty groan when turned in either direction. The fluid in the reservoir was also frothy white. To fully bleed it required the engine and reservoir cap to be off and the wheel turned full lock left to right about 30 times. To do this I raised the front of the car on axle-stands so the wheels were still touching, but with hardly any weight on them. The first turns lock to lock gulped the remaining fluid right into the system and so much air was coming out I kept re-checking the pipes for a leak. Eventually, the reservoir had swallowed the last of my bottle of fluid and is just about sitting up to the minimum mark, but still bubbles were popping up as the wheel was turned. The lock to lock business continued with me and my dad taking turns for quite some time until there were finally hardly any tiny bubbles rising to the surface. This whole thing was a job in itself, but the pump is very quiet now and the steering assistance is back.

Exhaust Vibration-Damper:
During the first tests there was an almighty rattle from the exhaust from tickover up to about 2k rpm. I assumed this to be because I had left off the exhaust 'vibration-dampers' that brace the bottom of the cat to the gearbox and stop it shaking. I discarded replacing it at first as, if you don't remember exactly the way it all fits together and start bolting your gearbox and exhaust back on willy nilly, then it's impossible to figure out. The long bracket with 3 holes fits around the edge of the gearbox bell-housing, held in by one of the large E14 and two of the smaller E10 Torx-bolts that hold the box to the engine. The connecting-rods then run from the foremost stud on the cat to the N/S stud on the bracket; and from the rearmost stud on the cat to the O/S stud on the bracket, as shown in the picture from TIS. Only trouble was, neither of the rods went anywhere near the brackets. I'm not sure if the entire engine and gearbox is in a slightly different position from before, or it's just the exhaust out of line, or both, but the eyelets on the left-right rod were about 5mm too long for the studs; and the front-rear ones were almost an inch too short. After 2 frustrating hours spent removing mounts and trying to relocate the gearbox / bracket to meet the exhaust I gave up and decided to modify the connecting-rods to fit the new gap lengths. The only remaining way to adjust exhaust position would be to loosen the two nuts holding the cat to the back of the turbo, only to do this requires the rocker-cover / injectors to come back off and I'm not doing that, for now at least.
The modified connecting-rods are below and, due to lack of time, are rather crudely done. I bent the left-right rod down about 3/4" at a steep angle to take 5mm length out of it and help bring it down to the bracket at a flush angle and works rather well. The front-rear was a bit less neatly done and makes use of a piece of 1mm sheet-steel, cut roughly to an inch square and bolted to the rod. It's not the best workaround in the world, but it gets the job done.
After all that, the 'vibration-damper' did not get rid of the rattle! Instead, I traced the annoying noise to the front rubber-mount a bit further down the pipe. The exhaust was banging right into the side of the metal bracket on the gearbox-mount and a bit of fiddling with the adjustable eyelet managed to separate them and killed the rattle dead, so there you go.

E21 316: Update + MOT Pass

After my disastrous few weeks I managed to get hold of a Bilstein strut-insert and get it onto the car along with the longer springs, meaning it was finally back on the road and in an state worthy of the MOT test. I cautiously rolled down to the test-station on Saturday and am glad to say the E21 passed with flying colours!

Bilstein damper is strong, but will be a pain with the short springs.

This was a relief considering the slightly dodgy seat-frames I made bolted through the floor-pan, which stuck out like a sore thumb when it was up on the ramps, along with the scuff marks where I've grounded the underside, but with the car at a more standard height off the ground this didn't see to bother them and there was no problem with the chassis at all.

Oddly, the guy told me that the split-pins were missing from the castle-nuts on my steering track-rod ends and this would actually be a fail under normal circumstances, but they could see I'd been working on it and decided to give me the benefit of the doubt. This was true, I'd had them off swapping the springs and hadn't bothered to replace the split-pins as they would be coming straight off again to put the short springs back. That was decent of them to let it go, as it would have been beyond frustrating to lose another week to something so trivial and shows just what a pain the UK MOT test is.

Folded up and with a 1/4 inch thick layer of
pallet-wrap to send as a parcel.

Spending on the E21 has been a bit out of control since buying the E30 seats and it is still in desperate need of the wheel-arches finishing off. By this point, I'm past what I can recoup if I sell the car. I'm still using my E39 as my daily, the E21 has had no use for nearly a month with no MOT and finally, due to a planned move, it's looking like I will have to let her go anyway, unless I can find somewhere cheap enough to store it. I had hoped to have the arches skimmed off and painted by the guy who did the respray, but money is tight so I will be buying a rattle-can and doing the best I can with them.

Thankfully, I've managed to generate a bit of extra cash to pay for the strut-debacle [this post], by selling some bits on eBay, like a battered old set of alloys, an E36 nose-cone and other bits I had lying around, as well as the original beige passenger seat from the E21 - I think I have enough seats for the car now. I hope the seat arrives to the buyer OK, as I had to practically shrink-wrap it to be able to send it Parcelforce [£27], pictured, as the original method of courier was just over £60!

My spare set of E21 ash-trays is not selling on the other hand and is still on the site here - http://www.ebay.co.uk/itm/181235987123.

E21 316: Burst shock-absorber woes...

SPAX adjustable - like hen's teeth.

Well, I've had a bit of a nightmare week. As I was replacing the front n/s shock-absorber with the new spring, ready for the MOT on Saturday, the strut-insert burst in my face. To get an extra couple of inches clearance at the top and get it under the wing I'd been pushing the damper down into the insert. I figured they sit quite far down with the short-springs anyway, but eventually, probably after doing it several times, I must have plunged it further than its full operating depth and it popped, sinking the insert completely into the strut.

You wouldn't think pushing it down would pop it, considering the forces on it under load, but once its down far enough the top seal just fails under the pressure of the oil. You can have SPAX, as with most adjustable-inserts, re-filled and the seal replaced if you can be bothered to send it back to the manufacturer and pay the cost, but with time of the essence I just bought a new one.

Larkspeed in Leeds were the cheapest, though the price had gone up from £90 to £112 [and £118 now for the shortened!] for a single insert, but they claimed to have the part in stock and would have it to me by Tuesday the latest. Today I rang them to say it'd been a full week since they rang to confirm the order and still no insert. After half an hour they rang me back to say the insert had been specially ordered from SPAX, who were now lacking correct parts and can't build them until the end of October. I wish they had told me that last week as I'm now waiting on a refund...

Bilstein - fixed damping-rate and pricey,
nothing but good reviews.

I rang DC Performance.co.uk, who also claimed to have the part in stock and it would take 2 or 3 days. Before parting with any money this time I asked if they could check the insert is definitely in stock, which they are not, so it's not looking hopeful for any existing stock anywhere. I will be contacting SPAX directly from now on.

Monroe Gas-Matic - strong, but ride too soft.

So what are the short-term options? There are no ride-adjustable inserts in stock and available now, so it looks like i'm now bound to non-adjustable inserts. Stiffened Bilstein inserts are £62 each, where OEM-replacement ones can be had for as little as £20. With the springs this low, I have no idea what would work best. The sportier, better-brand damper might last longer under the stress and be a better match for the adjustable SPAX on the other side. Alternatively, the cheap, softer damper might compress better under the load and a pair will only cost £40 should the o/s one need swapping too. Another option is to replace both with Monroe gas-filled dampers for £123. The blurb says they are a heavy-duty design for trucks and vans, but according to this thread they are just too soft and will cause me to bottom out. So, £60 for one Bilstein it is, or take a chance on a cheap KYB. Hmmm, stress.