RTAB replacement DIY
- Thread starter stupot67
- Start date
Nelly Welly
Active member
If anyone has a sketch or drawing then maybe we can get a couple made reasonably cheap and just pass em round the members who need them. ?
Planning on doing mine over the Xmas break as I'll have two weeks off, and plenty of time on my hands to take my time. Whenever I am working to a dealine I end up breaking something.
Making your own tool is doable for a a few quid, just some threaded rod, washers and some big impact sockets (not sure of the size) but for £35 for a tried and tested tool I'd rather do that - all the better if a few others want it and share the love.
Edit: Just seen your post Stu, please let me know how it looks, I think u have another few weeks yet before I commit.
Making your own tool is doable for a a few quid, just some threaded rod, washers and some big impact sockets (not sure of the size) but for £35 for a tried and tested tool I'd rather do that - all the better if a few others want it and share the love.
Edit: Just seen your post Stu, please let me know how it looks, I think u have another few weeks yet before I commit.
If you follow the official BMW procedure (TIS) you mark the position of the trailingarm carryhub.
But that is something you should always do if you see slotted holes :wink:
When you replace with an OEM bushing or meyle/OEM style, there is a procedure written in TIS how to mount the trailingarm rubber/hub properly with pretension/preposition.
I'm not exactly sure why they do this/advice this.
For PU bushings this doesn't apply (it works like a bearing instead of a bushing
)
But that is something you should always do if you see slotted holes :wink:
When you replace with an OEM bushing or meyle/OEM style, there is a procedure written in TIS how to mount the trailingarm rubber/hub properly with pretension/preposition.
I'm not exactly sure why they do this/advice this.
For PU bushings this doesn't apply (it works like a bearing instead of a bushing
)GuidoK said:If you follow the official BMW procedure (TIS) you mark the position of the trailingarm carryhub.
But that is something you should always do if you see slotted holes :wink:
When you replace with an OEM bushing or meyle/OEM style, there is a procedure written in TIS how to mount the trailingarm rubber/hub properly with pretension/preposition.
I'm not exactly sure why they do this/advice this.
For PU bushings this doesn't apply (it works like a bearing instead of a bushing
Your right GuidoK, I measured the position of the carrier in relation to a datum point on the arm prior to removing the carrier and bushing, the main issue with standard bushes is that they have no positive lateral stop/location position when installing them - you just have to centre it as best you can, hence despite pre-loading the position and marking the carriers position, your still going to need to get the alignment checked.
Stu.
stupot67 said:Bit of an update....
Ended up buying a RTAB tool, used it to remove the originals (60K and to be honest perfectly O.K) - and fitted a pair of Meyle HD bushes......So if anyone is interested in borrowing/buying the tool let me know, it works a treat
Stu.
How much to you want for it
not to worried about putting the alignment out as I would take it to be done afterwards. I would mark the carrier position and get it back as best i can but i don't understand this pre-loading/pre-tension :? can someone please explain
jan_tekin said:stupot67 said:Bit of an update....
Ended up buying a RTAB tool, used it to remove the originals (60K and to be honest perfectly O.K) - and fitted a pair of Meyle HD bushes......So if anyone is interested in borrowing/buying the tool let me know, it works a treat
Stu.
How much to you want for it
not to worried about putting the alignment out as I would take it to be done afterwards. I would mark the carrier position and get it back as best i can but i don't understand this pre-loading/pre-tension :? can someone please explain
Hi,
I paid £35 for it, I would be happy with £25 + P&P or you and whoever else are planing to change the bushes (There were a couple of others earlier in this thread), are more than welcome to borrow it and pass it along to the next person and so on that way it will minimize postage, also once you've changed them, chances are you wont be doing it again anytime soon, hence this thread in the first place (I've got a cupboard in my garage fully of special tools for cars I haven't owned for years!)
Let me know what you want to do.
Stu.
jan_tekin said:I would mark the carrier position and get it back as best i can but i don't understand this pre-loading/pre-tension :? can someone please explain
I only have a dutch version of TIS on my pc here but this is (in dutch) the advised procedure regarding this:
http://audio.home.xs4all.nl/zooi/z4/div/tis/trailingarmrubber.pdf
...There is an online tis with all in english but too much hassle to search the specific page in that website so deal with this very logical foreign language :lol:
They write that you have to mount a special tool on the drive flange, and put the arm in a special position before you mount it in the chassis. As an alignment for the bushing itself.
(in another part they also note that the rubber itself has to be pressed in a certain position too, there is a split in the outer metal bushing case that has to correspond with a line (in the casting) of the trailing arm).
I think it is because the rubber bushing is asymetrical in design (maybe a hydrobushing), and they want a specific orientation and specific tension (or better: lack of tension) when the car sits on its wheels. If you normally mount the bushing, the trailing arm is all the way down, and that is not the way it sits when it's on its wheels. If you don't measure it up like described in TIS it may be that the bushing is under constant tension when it sits on its wheels (once the bolt that goes through it is tightened).
That might result in premature failing of some sort if the rubber is under constant strain (and bigger strain when bumps are met).
But as I said, this only applies to the traditional rubber bushings. All poly bushings act like a bearing, so they can swivel without any tension. The poly ones also all have trailing limiter kits build in (also more or less because of that bearing like design)