Monday 13 October 2014

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.

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