smutly Posted June 16, 2004 Share Posted June 16, 2004 Can anyone advise what the thread size is in the chassis for the rear suspension front radius arm/watts linkage. I need to move my watts arm up from the lower to the upper mounting position and the thread looks like it has plently of paint in it. I thought I might tap it out but I'm unsure of the thread size. looks like the rear wings will have to come off to do this, so I want to make sure I'm all tooled up before I start! Link to comment Share on other sites More sharing options...
F355GTS Posted June 16, 2004 Share Posted June 16, 2004 Smutley Is it threaded, mine are a bush with nut and bolt, I think the thread is 3/8 UNF Mark Link to comment Share on other sites More sharing options...
Sheds Moderator Posted June 16, 2004 Share Posted June 16, 2004 It will be a UNF, if there is a hex on it then measure the size. 3/8 UNF bolts usually come with a 9/16 head size. 5/16 UNF - 1/2" AF, 1/4 UNF - 7/16 AF, these are the most common sizes on small sports cars. I imagine 7/16 UNF is 5/8 head, might get a few of these. Link to comment Share on other sites More sharing options...
elie boone Posted June 16, 2004 Share Posted June 16, 2004 3/8 UNF Link to comment Share on other sites More sharing options...
smutly Posted June 17, 2004 Author Share Posted June 17, 2004 Thanks guy's I'll borrow a tap from work and give it a go (carefully) Link to comment Share on other sites More sharing options...
F355GTS Posted June 17, 2004 Share Posted June 17, 2004 Smutley I'm still convinced they are not threaded, checked both '92 and '95 cars today and they are both Allen Bolts from the inside with a nut on the wheelarch side. You might have to take the seat out to remove Mark Link to comment Share on other sites More sharing options...
Bob Corb Posted June 18, 2004 Share Posted June 18, 2004 My 01 car is threaded. It a 96MY SL chassis so I bet they changed in 96. Just take it easy with the tap. You dont want to snap it deep inside the boss and have to spend 3 hours with a dremel grinding out the remains, just like me.... BC Link to comment Share on other sites More sharing options...
AMMO Posted June 18, 2004 Share Posted June 18, 2004 Smutley If it was my car that had a threaded bolt fixing I would drill it out and install a through bolt and nut. My car was originally like this. In my opinion this bolt is a bit on the small side and it scares the crap out of me. I have fitted Unbrako 12.9 cap heads. I change them once a year. I deliberately bought bolts that were too long and cut them down so as much shank as possible goes through the radius arm and the bush in the chassis. I have read postings from Blatchatters who have had these bolts fail in operation. The car rear wheel steers itself and is difficult if not impossible to control. The bolt brakes at the root of the thread leaving a part in the threaded boss. To my knowledge this has only happened to cars with a threaded boss in the chassis. I also think this bolt should be in double sheer instead of single sheer. In other words the bolt should be supported on the outside by a bracket or clevis. I may get around doing this to my chassis at some point. Maybe I'm a bit paranoid but I don't want to be sitting in may car accelerating out of a corner if this bolt lets go. I'm sure plenty of people have the threaded boss setup and have not had a problem. The ones that have probably don't want to experience another bolt failure ever again. If you intend to upgrade to the earlier setup and you're not capable of doing it yourself pay somebody who knows what they are doing to do it for you. Shouldn't be expensive. Just my opinion. AMMO Link to comment Share on other sites More sharing options...
elie boone Posted June 18, 2004 Share Posted June 18, 2004 Ammo, The original set up is fine BUT when they are torqued up ( as hard as you can, yes i know this is not really as it should be ) just make sure that the rear is supported under the de dion so that the radius arm is in its " driving position " Apart from the first seven i have serviced i never had one failure on this bold. The same for the lower bolt on the front shock absorber. Check then both regularly, at least every 6 months or after every track day. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now