Radius Arm setting

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Monte92
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Radius Arm setting

Post by Monte92 » Fri Feb 01, 2019 5:45 pm

Hi, despite having the car re-gassed , which has hugely improved the ride, I am still having some issues when the near side rear hits imperfections in the road, the car seems to lurch to the left at the rear and to the right at the front , not by much but disconcerting. I was going to check that the radius arm which I know was replaced was tightened at the correct height setting. The Haynes manual is not to clear on if this should be done while the system has been drained or after refilled. I assume it should be when no fluid is in the system can someone let me know the correct procedure. The car sits correctly on the road , all the rubber bushes around the car seem in good order , no loose mounts or anything else that I can see, clutching at straws now!
thanks
John

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Gasman
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Re: Radius Arm setting

Post by Gasman » Fri Feb 01, 2019 7:54 pm

If the rear radius arms are not correctly re-tensioned then the car will sit either tail down or tail up. I am sure Ian Kennedy (assuming he re-gassed your displacers) will have done this correctly or advised you if the pivot shafts are seized.

The correct procedure is to de-pressurise the system on the side you're working on. Make sure you place a trolley jack underneath before depressurising otherwise there may not be enough clearance. Jack up and remove road wheel and place an axle stand to support the car. Undo the big nut on the inner side of the pivot shaft just enough to allow the displacer to drop. If it is not possible to move the displacer and the nut is obviously undone then it is likely your pivot shafts have seized. As I said above, I am sure Ian Kennedy will have advised you if that was the case. Place another jack under the radius arm and jack it up until the distance from the middle of the hub to the wheel arch is 11.2". Make sure the displacer is pushed up against the reaction rubber and tighten up the inner nut on the pivot shaft to 120 lb ft. Re pressurise the system. Bob's your uncle.

If the pivot shafts are seized life gets a bit more difficult...

Your symptoms don't really fit with this being the cause. Are the steering rack bushes OK and I presume there's not play on the upper and lower front ball joints
Martin
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beiderbecke
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Re: Radius Arm setting

Post by beiderbecke » Fri Feb 01, 2019 9:25 pm

I concur with Gasman. If the displacer is seized on the shaft, the movement of the radius arm is transmitted to the outside rubber mounting, and as the shaft is keyed to the rubber mounting by a D-shaped hole, the movement winds up the rubber mounting which in time collapses. To check, make sure the nut is in the middle of the hole of the mounting - if not it is breaking up. If the displacer is seized, it follows that the radius arm bushes are seized as well, which is not good news. With regard to Bob - sometimes he can be your auntie too...

Check the rear butterfly bushes on the front lower wishbone - sometimes the car gets jacked up on these and they get flattened which restricts movement of the arm.

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Monte92
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Re: Radius Arm setting

Post by Monte92 » Sat Feb 02, 2019 6:17 pm

Thanks for the advice, Ian never mentioned anything was seized so i will look further afield , I will check all the bushed on the front of the car see if i can find anything Thanks

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Gasman
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Re: Radius Arm setting

Post by Gasman » Sat Feb 02, 2019 7:08 pm

I've had a look on the Kennedy's Fb page. He's posted with 42 photos of your car which I guess you've seen. The O/S pivot shaft was indeed seized but Ian managed to free it with his expensive new hydraulic press. The N/S released more easily. From what I can see the crosstube mounting rubbers look OK. Ian re-assembled with plenty of copper grease and he will have correctly pre-tensioned the radius arms. There was an issue with one of the mounting nuts which he sorted out.


What this means to me is that the rear suspension should be OK.

A simple thing; are the tyre pressures correct? They need to be squidgy as tyre compliance is part of the suspension setup.
Martin
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Owner of:
Oldest known surviving wedge, hand-built 15th Pre-Production Wolseley in June 1974
Last Ambassador down the line in November 1983, Austin Ambassador VDP

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Monte92
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Re: Radius Arm setting

Post by Monte92 » Tue Feb 05, 2019 11:02 am

Hi I( am sure the rear suspension is fine i have a feeling its a bush at the front so as soon as the weather picks up ill have a good look around the front .
Ill also drop the type pressures a but as well, they are 26 all round at the moment

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Gasman
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Re: Radius Arm setting

Post by Gasman » Tue Feb 05, 2019 12:44 pm

Tyre pressures of 26 should be fine for the front tyres but I would suggest you reduce the rears to 24 psi. However, that is fine tuning and won't solve your problem.

What puzzles me is why this problem only skews the car to the right when you hit a bump on the left side of the car. That seems counter intuitive to me but it is what it is. Whatever, as with all such problems, it is a case of working through methodically gradually ruling out possible causes. Don't forget the tracking which alters dependent on ride height (or on suspension movement).
Martin
Club Treasurer


Owner of:
Oldest known surviving wedge, hand-built 15th Pre-Production Wolseley in June 1974
Last Ambassador down the line in November 1983, Austin Ambassador VDP

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