Lurch - But not the Adams Family Type!

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BrianC
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Lurch - But not the Adams Family Type!

Post by BrianC »

Successfully passed MoT with no advisories :) ready to head off to have fun :twisted: on some quiet Devon roads this weekend. However I noticed that when I accelerate the car does a little lurch to the right, and when I lift off suddenly it does the same to left. Checked all the main suspension bolts, hubs etc.(MGB all round) but nothing appears loose. Any suggestions please?
steveshaw
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Re: Lurch - But not the Adams Family Type!

Post by steveshaw »

Hi, my BRA289 did the same, I had removed some leaves from the rear springs to get the ride height, this however allowed the torque reaction of the rear axle to wind up the springs even with anti-tamp bars.I kept replacing leaves one at a time until it stopped. I did consider installing some of the leaves "upside down" so it straightened out the spring but kept the stiffness, but as I have never heard of this being done I have never tried it, so I'm riding a little high at the moment.
Steve
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clive
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Re: Lurch - But not the Adams Family Type!

Post by clive »

Glad to hear you are getting out this weekend. Up here we had quite heavy snow overnight and hail showers throughout the day. Needless to say, the roads are covered in salt again so weekend driving seems to be a no no.
Cheers, Clive.

(If I'm not here I'm in my workshop or on the golf course!)
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David Large
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Re: Lurch - But not the Adams Family Type!

Post by David Large »

steveshaw wrote:Hi, my BRA289 did the same, I had removed some leaves from the rear springs to get the ride height, this however allowed the torque reaction of the rear axle to wind up the springs even with anti-tamp bars.I kept replacing leaves one at a time until it stopped. I did consider installing some of the leaves "upside down" so it straightened out the spring but kept the stiffness, but as I have never heard of this being done I have never tried it, so I'm riding a little high at the moment.
Steve
My BRA289 is fine. It has anti tramp bars and reprofiled MGB leaf springs. When we first built the car I put spacer blocks between the spring and the axle and that didinduce a slight effect as described.

David
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Bald surfer with a BRA 289, Porsche 968 Coupe and a Radical PR6!
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StewbieC
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Re: Lurch - But not the Adams Family Type!

Post by StewbieC »

Any movement in front suspension can influence this. Make sure top wishbone / lever dampers are fixed down tight!
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BrianC
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Re: Lurch - But not the Adams Family Type!

Post by BrianC »

Looks like today will be spent underneath re-checking everything. All seemed OK last year, and the only thing I have done this year after the MoT was to take it out for a test run (= a good thrashing) and time some 0-60 runs, maybe I overdid something?
It will be a pity if I can't take it out as I was particularly looking forward to this part of the trip, secure steering essential!

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Roger King
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Re: Lurch - But not the Adams Family Type!

Post by Roger King »

Oh yes, done Porlock as a closed road on a number of occasions in the Healeys - once in the snow, which was interesting. That's where I learnt not to use silicone brake fluid, on the way back down after my second run first time we visited.
I don't remember going quite that fast, though...
morgy
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Re: Lurch - But not the Adams Family Type!

Post by morgy »

I had the same thing on my Atom one weekend.. Turned out to be a difference in the tyre pressure.. they only run 12-14 psi...
BrianC
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Re: Lurch - But not the Adams Family Type!

Post by BrianC »

SOLVED!
Checked front suspension thoroughly along with tracking just in case and all appeared to be in good order. In the interests of safety took the car down to my local garage in case I was missing something obvious or otherwise. The guy who runs it is an old time engineer, remember those, and within 5 minutes of putting her up on the ramps turned to me and said " Why don't you tighten up those ****ing nuts you tosser? " pointing to the offending items on the bottom of the U bolts holding the axle to the springs. I then proceeded to wind them up more than half an inch on the nearside and a quarter of an inch on the off side! A run up the road proved him correct, and me feeling like an idiot. It was only later that I recalled having re-bushed the rear suspension the year before, and I guess that the rubbers settled in leaving the free play. So that's a blast down to Haynes Sunday Breakfast Club required to confirm I think!
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