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Gavin Waddell

Rear beam rebuild questions

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Gavin Waddell

I'm going to be rebuilding my beam( its all apart and i'm going to freshen it up paint wise) but have a few questions when it will come to the reassembly.

 

1: The shafts our good and have no wear in them, so wont need to change them, but i read that people leave a 5mm recess between the end of the shaft and the trailing arm i'm guessing this is for the spongy seal to sit in and not get squashed ?

So one of the shafts is recessed by about 4mm and the other one is flush, would it be ok to put them in a press and push the shafts in to create a recess for the seal?

 

2: i have identified that there is a L&R ARB end Plate, but are the rubber seals the same for both sides ? and always fitted with the rounded edge facing into the shaft?

 

3: The Cup which the trailing arm shaft seal sits in can this be pushed all the way onto the beam tube? And then the seal is just pushed or do i have to leave a little tolerance (thought that i read it on the, site somewhere) ?

 

4: Im running bilstein B4's all round with Eibach springs up front and was wondering what dummy rear shock length have people used to set the ride height with a 30mm drop .

 

Think that's  it, if any one has any other tips or tricks i am all ears

 

Thanks Gavin

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welshpug

All the specific  detail is covered in one of my threads a few years back, but specifically;

 

2mm recess for the shaft, not 5mm. 

 

the seal collar is set 2mm gap, not fully seated, seal pushed in fully and then with the torsion  bars fitted they should be set to a 0.05mm gap and locked in position  with the stud and locknut.

 

The arb seals and bush are not handed.

 

Try 312mm

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Gavin Waddell

Ok so 2mm for the shaft, you reckon its ok to use a press to get the proper distance ?

 

so if i understand  i put the collar on the beam tube, tap into place until it is sitting 2mm from the end of the recess? fit the seal all the way in (is it easier to fit the seal to the collar externally) then fit? then build up the rest of the beam and then once that is done tighten up the shouldered bolt to pull everything together and set collar distance @ 0.05 mm, then lock it all off.

 

Just a thought do you do the torsion bars first or the ARB bar first?

 

you really are a wealth of knowledge Mei, thanks again, for helping me out.Insert other media

 

Gavin

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welshpug

Yes use a press, place a spacer 2mm thick and press down till the shaft stops against it.

 

Torsion bars first, the arb gets in the way and also needs the clearance setting at 0.5mm each side.

 

Seal collar fitted first, pop the seal in, fit the arm.

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Leslie green

Following :D 

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Tom Fenton

Don’t get too hung up about the 0.05mm, if you look at the main seal there is a lip for the shaft, then another that seals against the top hat. Set the adjustment so that the top hat is sealing on that lip, without flattening it totally. Too loose and that lip won’t do its job sealing. Too tight and that lip will quickly be worn away and come off the seal. 
The cup that the seal fits in is tricky to assemble, the main thing really is to make sure that the seal is square in the cup and  the cup is square to the tube. 

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jord294

Hopefully you realise bearings are fitted a specific way, especially inner bearing. 

 

Bearings, crossmember seal, seal, collar over trailing arm shaft should all be an interference fit. Genuine parts prove this, especially the crossmember seal. 

 

The rounded edge of the arb lever seal its against the lever, with the squarer edge pointing towards inside of trialing arm when fitted. 

 

The arb is fitted with the lesser splines and lever from the left side and then the other arb lever wound on from right hand side.

 

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Gavin Waddell

Ok thanks for that everyone for that has cleared things up for me. I have a few questions and also some thoughts.

 

Im going to get all the bolts zinc plated, and the rest  of the parts ( beam tube, torsion bars etc )will get sand blasted and painted.

I was looking at the ARB levers and was thinking i cant plate them because the splines of the torision bar wont fit any more?

 

Another thing are all the nuts   m12x1.25 ? ( Tom Feton thread) as these will also need changing.

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jord294
1 hour ago, Gavin Waddell said:

I found this thread on a french site which explains evertthing in french but has some really good pi tures of disassembly and reassembly of the rear beam.

https://automobile-normande.forumactif.com/t7-remise-en-etat-train-arriere-205-et-309-gti-et-autres

 

Not bad write up, but few things I see wrong.

 

Grease nipple mainly.

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Gavin Waddell

The french love a good nipple i think, what else didi you find wrong, out of interest.

 

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welshpug

They specify an incorrect thread  pitch to draw the arb end plate off.

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Leslie green

That's a very decent writeup will be a good help refitting mine cheers 

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jord294
2 hours ago, Gavin Waddell said:

The french love a good nipple i think, what else didi you find wrong, out of interest.

 

Crossmember seal fitted incorrectly. 

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Gavin Waddell

Which way round should it go? As i am about to start putting g mine back together this weekend and dont want to get it wrong.

 

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Gavin Waddell

Back with same question about the main seal , which side does the this side go ( red arrow) against beam tube or against trailing arm.

20221112_170125.jpg

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Gavin Waddell

Just spent 5 min looking at the seat and i think the ribbed part goes into the cup and the flange goes against the trailing arm  top hat. Am i correct ?

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Leslie green

Red arrow is to trailing arm top hat, ie lip of seal touches trailing arm

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dcc

You need to be careful at this point with setting clearance

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Gavin Waddell

I haven't got that far yet waiting for ally bits to come back from the platers.

 

As for the clearence i know that i dont want to set to tight, i think it was mentioned in one of the posts above.

 

I do have one more question, the cup that vame with my bearing kit has a radiused edge on one side and the other is straight. Am i correct in thinking the radius edge sits against the beam tube and the straight edge aainst the seal.

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Leslie green

Did you get an further with the Gavin , I'm starting mine soon . I had trouble getting the 4 bushes on the tube and danaged one so need to cut them out again which is a right pain .Just too tight a fit .

The little tophat collar that goes on the shaft whats the best way to get it on without damaging it ?

Edited by Leslie green

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welshpug

A piece of tube, needs to be longer than the section of shaft, i have a spare pieve of exhaust pipe to hand.

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Tom Fenton

The best way is to press the shaft through the top hat, while pressing the shaft into the trailing arm.

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Leslie green

Cheers lads the shafts are already fitted ..I have quite a few pieces of tube lying about all too big or too small then I saw this vintage starting handle perfect for the job ,nice wide area to spread the load a few whacks and they were in then  I thin used a sandpaper type 30mm flapwheel in the drill to clean up the area the 4 bushes sit in on the tube to make fitting the bushes a bit easier after getting one stuck halfway in. I had to destroy 2 bushes to get that one out again and a Black and Decker powerfile could get in to wear down the sleeve as its impossible to get at it to knock it back out after the rubber is drilled out. I had tried a hacksaw without much success this time .

 

52677435910_0fe042972e_k.jpgIMG_20230208_153638 by Leslie, on Flickr

Edited by Leslie green

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