AC Owners Club Forum
AC Owners Club Forum => Mk IV, Superblower, CRS and other Continuation Cars Forum => Topic started by: westcott on July 05, 2014, 12:06:33
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As some of you may have the same noise problem or maybe solved it i would like to collect solutions for the problem here again.
My car was squeeking from the first day on i owned it. Some times after havy rain drives the noise was a bit reduced but not eliminated completely.
I replaced/checked every detail of my rear suspension but it still speaks to us during every ride.
What i did so far:
- replaced worn out suspension rubber bushings by PU parts rear and front
- replaced the lower bearing at the koni's
- cleaned, checked, greased and replaced all rubber dust boots
- cleaned, checked, greased all ball joints
Last week i applied some low viscouse miracle lube to all moving interfaces at my rear suspension, no success.
But, a vew days later, we had a real sunny Cobra meeting tour and after a 15 minutes brake (my wife was still sitting in the car) the noises were gone completely for the rest of this and the following day !!!!!
Two days later the noise was back.....and it definitely is caused by the rear suspension parts.
I think during the brake the only difference to all past situations was that the suspension was a bit preloaded and the warmed lube reached places it could not reach before.
Who has solved this problem in the past and how? Any help is highly appreciated.
Uwe
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Hi Uwe,
Has the inner joint on the lower-rear-wishbone rear link got a grease nipple? (that is the adjustable joint that connects the wishbone link to the chassis). Some early cars did not and that can cause a squeak.
John.
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Hi John,
i'm going to name the parts as explained in the cobra 427 chassis instruction book:
I think you mean the trailing link to chassis bearing (in front of the rear wheel), there is no grease nipple. Edit: This is a ball joint as well, no nipple.
The trailing link to lower wishbone has a ball joint, no grease point.
The lower wishbone inner bearing to chassis i have to check.
Edit: No nipple, just a bushing, is it the position you mentioned?
The only grease nipples on my rear suspension are at both ends of the so called chrome pin connecting the lower wishbone to the rear upright.
Could you post a pic with the position of this mentioned grease point?
Thanks, Uwe
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Hi Uwe,
I don't have a 427 chassis book to refer to but it sounds like the 'lower wishbone inner bearing to chassis'. 1082 had the same problem and I drilled and tapped the boss to take a nipple. I will try to get a picture to confirm.
John
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Hi Uwe,
are we talking about this grease nibble?
(http://i143.photobucket.com/albums/r138/dkp_cobra/Cobra/IMGP2980_zps962e5069.jpg) (http://"http://s143.photobucket.com/user/dkp_cobra/media/Cobra/IMGP2980_zps962e5069.jpg.html")
I think, the pre-owner has added this after one of the bushes had to be preplaced due to lack of grease. As I mentioned one day I had never the squeak problem.
Peter
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Peter,
Yes, that is the one - thanks for posting the picture.
A 90deg. nipple makes it easier to grease but otherwise the same.
The complicated joint has rubber-ring seals but they don't work well therefore re-greasing is necessary to stop squeaks.
John
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Thank you John and Peter,
disassembled the rear lower wishbone yesterday evening, put in the grease nipple, greased it completely and assembled it again. I will see if the noise is gone this afternoon.
After complete dismanteling i saw that the rose joint in the lower wishbone to rear frame bearing had lots of rust, water and showed some wear.
I will replace it during the winter but have not found the correct rose bearing today.
Can someone bring up a source or part number for the rose bearing?
One of the two O-rings was splitted and i measured the other one, it should be 30mm x 5mm.
The rose bearing ring has 39.98mm outer dia and a width of 11.01mm, the ball has a 26.06mm inner dia and a 17.40mm width.
BTW, i used self tapping/forming, hardened, 90 degree grease nipples, no need to tap a thread into the hole.
Thanks for your support,
Uwe
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The internals of the lower wishbone inner bearing to chassis looks like this after a quick clean up, what you see is the bearing outer ring sitting in the wishbone, kept in place by ring and groove.
The ball is rotated out in this picture.
(http://i74.photobucket.com/albums/i266/crendon_2006/P7122854_zps62a68e08.jpg) (http://s74.photobucket.com/user/crendon_2006/media/P7122854_zps62a68e08.jpg.html)
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The bearing ring outer side has no grease hole or groove. If you drill the hole in the middle of the lower wischbone it will be directed to the bearing and grease flow is blocked. Therefore i ground a small distribution groove going from the drilled grease hole to both sides of the bearing ring. So grease will be distributed to both sides of the bearing easily and kept by the O-rings. Don't apply too much grease with your press, the grease will push out one or two o-rings and your sealing is gone again.
(http://i74.photobucket.com/albums/i266/crendon_2006/P7122855_zps67fa9264.jpg) (http://s74.photobucket.com/user/crendon_2006/media/P7122855_zps67fa9264.jpg.html)
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The ball itself is guided by this adjustable assembly. The nuts can position the ball (in the installation the ball is sitting in the bearing cage/ring) to front or rear direction to adjust wheel alignment if necessary. On my car the wishbone was adjusted to the most rearward position possible. The adjustable, bored out threaded pin is sitting between the metal flanges, kept in place by a screw as you can see in Peter's picture.
(http://i74.photobucket.com/albums/i266/crendon_2006/P7122858_zps78babfc4.jpg) (http://s74.photobucket.com/user/crendon_2006/media/P7122858_zps78babfc4.jpg.html)
(http://i74.photobucket.com/albums/i266/crendon_2006/P7122859_zps7007028f.jpg) (http://s74.photobucket.com/user/crendon_2006/media/P7122859_zps7007028f.jpg.html)
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After the bit of metal work i cleaned all parts, preloaded the assembly with grease and installed the parts back to the car.
The left hand side was done Thursday last week, the opposite side on Saturday last weekend.
The result ????
The squeek is gone completely !!!!!
Thanks John for the info and Peter for the picture.
After the disassembly i saw that the ball and bearing ring showed some wear but will do its job for the rest of this year.
To one of the bearing rings was the following part number electric scribed:
RB7 210 ML
It is the same kind of bearing as used for the lower Koni mount but with different dimensions.
I could not find a reference in the www, does someone has a source for this part?
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O.K. maybe not correct written to the bearing so the 7 could be a J without lower bow and the part number could be:
RBJ 210ML, makes more sence, doesn't it?
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Update:
Found the part RBJ 210ML in the UK, can order them online, payment by Paypal is possible, delivery worldwide, delievery will take 2-4 days.
What a perfect day !!
RBJ-210ML - ROD END BEARINGS
Also known as RBJ210ML, dimensions:
26mm x 40mm x 17.5mm x 11mm.
They match the measurements i have taken from the old parts with a simple caliper:
26.06mm x 39.98mm x 17.49mm x 11.01mm
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I (MKiv crs) found that the 2 nuts with o ring carrier groves needs threadlock/locktite to stop them coming apart and making the rear suspension very "sloppy". (i failed my MOT a few years back on this. It also leads to some rear steering.)
Also the long bolt that goes through this tube and the nut on the end(not much space and angled chassis supports to insert) can work loose as the bolt threads need to be in the "nyloc" so some spare nylocs should be carried(dont reuse or add locktirte)
I did wonder if some people have "shorter nuts" or aircraft locking low profile nuts there.
I have been told from an authoritative source that some of these rear bearings come in various sizes (varies by car) so measure up before ordering (40mm on later cars with some imperial 1.5" on earlier cars)
Here is the tube on my car with the rose joint off(CRS)(http://i270.photobucket.com/albums/jj101/flyinghorse_lc/Rearsuspensiontube_zpsc3535618.jpg)
Graham
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Hi Graham,
the tube and nuts are the same, just the nuts on my assembly where not symetrically adjusted, the position i showed in the pic is the one the assembly showed in the car from the beginning.
The dimensions of the bearing are defined by the part number, so have a close look at this number.
RBJ-210ML has metric dimensions.
Uwe
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It wonder if this is really an adjustment point or they just moved there? (On one side mine was able to open up) Was there any thread lock on them when taken apart? Peters in his photo are " centred" as are mine ). Wonder what others have?
I guess if they are like this both sides they were used for adjustment/was done deliberately. Bit like some weird caster at the rear. Does anyone know ?
My adjustments at the rear are toe and camber with camber being done using the top screw in single rose,and toe by the small link rods with flats.
It was Gerry Hawkridge that told me they come in differing sizes and he stocks them. I had unfortunately put mine back together before measuring and did not want to remove to check.
Graham
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I had to apply a lot of force using a vice to break the two nuts loose. So there was no unintended movement, looked like a defined adjustment and with this specific setup we measured the following at the rear:
Camber:
LH 1°14', RH 0°21', set value 0°30'
Toe out:
LH -0°17', RH -0°19', set value -0°15'(total -0°30')
Camber values are out of spec and will be adjusted end of the season.
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Many years ago I asked the factory how they set up this joint from new and they said 'about in the middle'. I assume they then used the forward radius rod (in front of the wheel)to set Toe. There must be a reason for use of this complicated joint and I would be interested to know if anyone does know why.
Incidentally, I know the Handbook specifies Toe Out on the rear but I think the general view is it was a misprint and should be Toe In (about 2mm) with 0deg.30min. Negative Camber.
John.
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Maybe this adjustment was for anti-dive/squat? The inclination of the pivot bolts would affect this characteristic, by adjusting the inclination of the lower suspension pivot axis. That would affect anti-dive more than anti-squat, due to brake torque.
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We added 500 km to the odometer since the repair and the squeek is gone. In the meantime the rod bearings arrived and will be installed after ECM in St.Tropez.