Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Roadster rear suspension fail

After recently hearing a knocking from just behind the driver's seat on my Roadster Ser2, I removed the offside rear wheel to investigate. I appear to have suffered a sheared mounting bolt on the anti-tramp bar. There is a useful note on GoMog at https://www.gomog.com/allmorgan/roadsterantitrampissue.html and the photo looks the same as mine. So, not uncommon, but how and where do I source and replace the bolt ? I'm guessing I will have to remove the U-bolts to remove the block and tap (as in thread) out the remnants of the bolt where it appears to have sheared ? And it may just be the way it looks, but the bush seems to be internally threaded which can't be right ? This is the first time I have worked on the rear suspension, so in removing the U-bolts, is anything ghastly going to happen like the leaf springs exploding apart ? Help !

Removing the underslung saddle block won't cause issues with the leaf spring but the chassis will have to be supported before you loosen the axle U bolts which hold it captive. It does appear it has a tapped hole within presently accommodating the sheared anti tramp bolt fixing. The tapped hole may have been the only solution if clearance wasn't available to accept a nut the other side of block. Its possible you can use an "easy out" to remove the sheared remaining part of the bolt, having drilled a liitle way down its centre. A matching bolt with the highest shear resistance could then replace it. Failing that a new sadldle block may be attainable.

As suggested in the GoMog article the use of only one anti-tramp bar is cutting things fine engineering wise but guess the arrangement has survived a number of years. A second anti-tramp bar and matching saddle block on the other side would be far better of course..

Easy out set below.



If you can loosen the forward end of traction bar and move it out of the way you may be able to do the job in-situ.

Thanks Richard for both your posts. I will make further invetsigations but now have some rather urgent domestic matters to attend to first.

I had one on my T16 powered +4. It failed, MMC couldn't supply a replacement so I took it off & frankly the car was fine.
But of coure the extra umph on a Roadster might make the back end more fun.

My S1 Roadster didn't have an anti-tramp bar. OK, you can drive it like that, but when accelerating sportily, the cardan shaft lifted and touched the rear underbody, which made a loud grinding noise. The S2 and S3 had an ATB. I had a second ATB fitted to the S3 and everything felt much more controlled. I even had a retrofitted Panhard bar removed because it added other unpleasant characteristics to the driving experience for my taste. But with two ATBs fitted I no longer needed it for cornering control.

Good to know, thanks. I figured that a second ATB would be good, I'll check the accessibility from abouve when I can, I seem to recall cautionary words about the battery getting in the way on the nearside. At least if I have to give in and seek some professional intervention, it's good to know the car would still be driveable to get there so to speak.

Interim update: with the driver's seat fully forward and several leather trim pieces lifted, I managed to access the front mounting of the ATB. Easy enough to loosen/unscrew. Once removed, I could see that there is no threading inside the bush, just a little wear from some graunching over a period of time I suspect. The end of the fairly massive sheared-off bolt was so hard that not even the special drills in the "Easy Out" kit I purchased (Amazon) made much impression (must've been one helluva whack at sometime to shear it ?). Centre punching it with the hope of loosening it, and some WD40, meant that eventually I could back it out by hand. I have ordered a replacement from Rutter's, which I trust will suffice on just the one side as per original.

Good result Peter I can see why you may thought the bush was threaded internally but it was likely just the thread markings in the grease within. There would be no reason for it to be threaded. I would have checked the markings on the bolt head to see if a higher spec one (read greater shear resistance) was available but I guess this had maybe been lost when the bolt sheared - likely due to long term fatigue.

Thanks. I couldn't really figure how anything threaded (apart from the saddle) could have worked. The shank and head will be pining somewhere in a ditch in the New Forest I suspect, so I couldn't check the inscription. And nothing available online that matches the high-strength requirement and dimensions (12.8mm clearance hole in the bush, which is 42mm long, and the sheared threaded end which I extracted is 19mm long), so I ordered a factory one. I was surprised how heavy the ATB is.