Rear Suspension Arm Corrosion

[PHILIP BUXTON]

SEE ATTACHED PHOTO Car was like this at last MOT 2 years ago ( I live in France) but was passed and I was advised to do something about it for next test now due in a couple of weeks.The actual area where corrosion is does not appear to be "load bearing" as plate is very thin.I have a friend who has proposed making a replacement "cover" for whole arm out of 2mm sheet and welding it on. Do you believe damage is dangerous and if it can be repaired what do you recommend? I am expecting the worse but don't want to have to scrap car . I do not see corrosion at other areas you mention on your site

 

[John Doe]

This seems very dangerous to me, you should do something about it as soon as possible. I think the best way would be to buy another suspension arm and replace it. The price should be ok, I sold two suspension arms and two torsion bars for 30 euros.

 

[malcolm]

I'm surprised the wheel hasn't fallen off. The pressed steel suspension arms (I've only seen them on French cars) do seem prone to corrosion. Should be inclined to find a complete rear suspension from a scrapyard and bolt it on.

Welding is possible, but would have to be to a very high (professional) standard, and the wheel might end up at the wrong angle.

 

[Steve Hennessey]

Malcolm, the pressed steel arms were used on the earlier 4's and the rear suspension set up is different from the GTL's.
Philip's one is very dangerous and I'm surprised it passed the MOT 2 years ago. I agree that it would be best to fit a complete second-hand unit if a good one can be found. I don't know if Renault changed the chassis throughout the production run, but if not then it would be better to fit the complete rear suspension from a GTL.

 

[John Doe]

All cars made in Slovenia (GTL and TL) have pressed steel arms. Only once I saw a different arm on a F4 but it was probably an import.

 

[Steve Hennessey]

Maybe Slovenia used the older tooling throughout the production run. I worked on the older R4's in the 1970's and distinctly remember that the rear arms were pressed steel. If the Solvenian 4's including the later ones use the same suspension as the early models then it would be interesting to know if the later GTL's in Slovenia used the same chassis as the GTL's in the UK and France. If so, then the later suspension on these cars would fit Philip's chassis.

 

[malcolm]

The '80s Spanish 1128s and the French 1126 also have pressed arms. Seems the GTL is the rarety. The monting point locations stayed the same throughout Renault 4 production, and as far as I know through different contries too, so all of the rear suspensions are interchangeable as units (though the handbrake moved from the front to the rear wheels in about 1983 so makes sense to get one with or without the handbrake (as appropriate).

Build spec is funny country to country. The '80s Spanish cars used a lot of 1960s and 1970s parts - amongst other details the chassis still had the cutaway ay the back that early cars had, and they had the metal parcel shelf.

 

[PHILIP BUXTON]

So bad news . Can just the one suspension arm be removed and replaced? I am sure this is way beyond my capabilities and I will have to try and find someone to do this depending on cost. How complex a job is it.

 

[angel]

The suspension arms were changed in 1977 to cast iron, together with the introduction of the fixed torsion bar mounts. I have heard again about the Croatian R4s having pressed steel arms, and I was wondering, do they have adjustable torsion bar mountings? (someone there with a Croatian R4???). I remamber seeing about ten years ago a 1978 Safari which had one pressed and one cast arm. The outer arm bush is certainly the same on both arm types. If the inner bush dimensions are the same,too, one can easily fit a cast arm on the existing inner mount. Fitting a complete "new type" rear suspension on an earlier chassis necessitates drilling the chassis as the inner mounting locating points are different.

 

[John Doe]

There are no Croatian R4's, they were made in Slovenia (Novo Mesto) but because we all were a part of Yugoslavia they are widely spread accros. If you could tell me what to look for I could check on my two R4's made in Slovenia (the third was cut to pieces and taken to the scrapyard).

 

[John Doe]

This is how it looks like on a 1988 GTL, ignore this yellow circle, it has to do with something else

 

[malcolm]

Fitting a complete "new type" rear suspension on an earlier chassis necessitates drilling the chassis as the inner mounting locating points are different.

Oops - I've been using the 1972 dimensions for my GTLs. Car sits about right and the suspension bolts on OK. What are the differences in the mounting points?

 

[angel]

Clementine you must be right... I never came across the situation of having to fit a "later" inner arm bracket on an "early" chassis. Fixed type cast iron mounting has three locating holes, sheet steel mounting has also three holes but spaced closer,plus the adjusting cam 12mm hole May I guess, can you fit a later inner mounting over the two 8mm holes and the cam hole?

 

[malcolm]

Had to go out and check (I'm not yet familiar with the early mechanicals) - the later arms use the outer two 8mm holes and the 12mm hole for the adjuster cam. Also the later chassis still have the three 8mm holes and the reinforcements for mounting the earlier suspension arms, so the rear suspension is interchangeable between early and late cars.

Of course that's all a bit academic as the rear hubs don't appear to be very interchangeable, though it might be fun to have two handbrakes - one operating on the front wheels and the other on the rear.