I'm posting this for my Dad who is restoring a 330 GTS and has discovered a problem with the rear suspension - his words; The rear shock absorber mounts on the 330GTS have dropped [collapsed], leaving the car sitting low by about one inch at the rear. In Cavallino 75 (July 93), it refers to this as a weakness in the chassis structure. A permanent repair has been devised and is documented in 'Prancing Horse no 51'. Does anyone have a copy of Prancing Horse no 51 or know what the modification is? All opinions/ comments gratefully received Thanks in advance Matt
Are you referring to the shock mounts on the body, accessed from above in the trunk? If so that would cause the shock to raise up, lowering the car. Can you post pictures? Morris
I think what you are saying sounds correct, I don't have any pics of the particular issue (or any decent ones of the car itself yet as Dad has not long acquired it) but will see if I can get some posted up. I'm not sure if this is a problem unique to the GTS or something also found on the GTC. Thanks in advance for any assistance Matt
Quoting from the Cavallino #76 issue: "The upper rear shock absorber/spring mounting ears tend to tear away from the chassis, resulting in the collapse of the rear suspension." Yes, there is a fix detailed in PH #51, and no I don't have a copy with me. The author (Dyke Ridgley) speculates that the additional weight of the GTC body (over the 275 Berlinetta) might be responsible for this issue. I don't know if that would relate equally to the GTS...... I hope someone will post with knowledge of the "fix". On examination of my car, I was relieved to find that had not happened to me. Coincidentally, there were failure issues related to the front suspension of GTC's as well; with a "fix" passed around in the '80's. No mention of this in the Cavallino article. I think this was mentioned in a post on Tom Yangs site. James
I don't think it should be difficult for any competent mechanic/engineeer to repair the damage and then design a stiffening fillet/structure to prevent it happening again.
If I am not mistaken I believe there was actually a factory bulletin about the rear top shock mount. I think it involved welding an added steel plate.....something like that. I'll look up my old GTC docs to find it and let you know. Should check my car too!!
More info from Dad Thanks for the info the ferrari bulletin would be useful. On close inspection the suspension brackets haven't collapsed but appear to have bent upwards this is shown by the fact that the rear of the bracket [the part welded to the round tube] is slightly curved and my mechanic says it should be straight .I don't think this would show up on a photo but you can try if you like. We are going to try and pull the bracket back down and into shape then weld a support plate under it to provide additional strength as suggested in Dyke Ridgeley's article, having now obtained a copy. To try and fabricate a new bracket would be a really tricky job as the access for welding a new bracket and inner tube to which it is fixed is extremely limited without cutting away some of the bodywork .
Yes the actual recall notice is on Tom Yangs site if you search the restoration diary for this date 11/16/06 or GTC Recall notice. Best, Yale
Hi Yale, I am pretty sure the recall discussed on the TY site was about 18 months ago and it concerned the front (upper) shock mounts. The sheet metal that makes up the box where the shock attaches actually tears. The factory called for bracing it. john
I need to have the rear upper mounts repaired on my GTC. Can anyone send me the article from PH#51? Or maybe Dyke can send a copy of his article? I was removing the shocks for rebuilding and found that someone in the very distant past did a lousy repair on both sides, and both upper mounts were moving and one side was only held onto the body by a thread of weld with much corrosion of the welds in the repaired ares. The top flange of the shock hid the damage. It wasn’t visible until the shock was removed. I knew I had a problem when I disconnected the lower end of the shock and could move the assembly up and down because the mount was flexing so badly. Having communicated with the previous 40-year owner of the car, this repair was clearly done before he had the car (which he bought in 1976). I’m amazed I didn’t lose the passenger side mount. It’s a mess. So, that article could come in handy. This is the only place in the car we hadn’t previously seen. Luckily, these two mounts are the only places on the car showing any corrosion at all. But what a lousy place to have to do repairs. I’m sure the rear metal shelf will have to be removed (or at least cut) to gain access to the top of the support tube. Oh well, my goal all along has been to ensure the car is brought fully up to snuff under my ownership. It’s only time and money….sigh. Image Unavailable, Please Login Image Unavailable, Please Login
Just bought a copy of #51 from ALBACO. $10. Seems like an excellent investment. The article in question is: Technote: Rear suspension Failure 330 & 365 by Dyke Ridgley
It is gratifying to see articles I wrote almost 50 years ago are still useful to Ferrari owners. Like you Kevin, I had no idea of the situation until we removed the rear shocks and found the upper inner fender panel (you can see where the shock was being pushed up against it in your photos) was the only thing holding the car off the ground!
you are sure it was not luigi in the factory on early monday morning after much lambruso and pasta in the night from sunday to monday?
The damage and/or presumed previous repair appears fairly similar to ones I corrected in Jim E's car 3-4 years ago and I'm convinced it hadn't been previously "repaired" (despite the claims of those who sold him the car when he mentioned it appearing sitting quite lopsided and they just propped rubber or wooden block between the shock loop and the package shelf bottom, which must've fell off right after he had taken the car for first drives). I thought it was just inadequately made by who ever designed, engineered and fabricated that part of the chassis. I remember receiving a copy & reading Dyke's article, but opted to take my own, slightly different approach by fabricating all new, heavy duty, thicker material mounting forks with longer/thicker, i.e. much stronger insert tubes and adding a thick plate on the vertical wall surrounding the mounting structure and bolting them to angled rectangular upright tubes inside the trunk. I believe the whole thing ended up strong enough that everything else in that cars rear chassis/suspension will fail long before my corrections. Oh, I didn't have to cut into the package shelf or any of the adjacent coachwork sheetmetal, but the job was quite involved, especially when having to do any cutting, grinding & welding inside the tight quarters of those upper shock towers and the trunk. While I did everything else, the final welding inside the upper shock towers were done by a 75 y.o. friend who is very experienced welder (of anything you can think of), laying on his back on a gurney-like rolling table with his upper body inside the wheel wells, while I lowered the car down to almost top of him and offered moral support or any welder adjustment, if needed.
So, as originally built, that upper shock mounting bracket was, indeed, an insert into the chassis tube?? From the factory? Here’s photos from TEAM CJ who is rebuilding a 330 GTC. I would have thought this is how it was done at the factory…weld the bracket directly to the chassis tube. Seems like a much better and stronger construction method. The idea of using a smaller tube attached to the U-bracket and slipped into the chassis stiffening cross tube and welded in place seems like a recipe for eventual failure due to the kind of corrosion I’m seeing on my car. Of course, no one at the time knew these cars would still be on the road almost 60 years later. Image Unavailable, Please Login Image Unavailable, Please Login
Timo - I don’t suppose you have any photos of the repair you’d like to share? Or any sketches? Thanks.
Kevin, I have/took plenty of photos, so if you wish to drop me a PM with your email, wait a day or two, I dig some out.
At the time of my aforementioned repairs I recall comparing the structural design & material strengths between 330 GTC and 365 GTB/4. While close to identical in design, 365 GTB/4 appeared to have been made slightly different & stronger, but also apparently received some improvements/upgrades (at least once) during their production timeline, which along with 330 GTC/S front shock upper mount ailment made me wonder about the mythical notion that PF constructed cars were somehow built “better”(?). And yes, I realize the chassis were made by someone else, but presumably to PF design, right ? Did 365 GTC/S chassis still suffered of these same issues or did they receive any improvements/upgrades during their production ?
BTW, here’s a link to Team CJ’s 330 GTC project page. Tons of amazing photos. And yes, I know the redone seats aren’t correct. I don’t care. I’m much more fascinated by the fact that they took this car down to the bare chassis and have photos of everything!! Quite a great resource! https://teamcj.com/1967-ferrari-330-gtc-bk/
