Chassis rivets repair - How?

Hello

I have at least 6 totally loose rivets in the mercedes 6600 chassis I am working on. I have removed some of them and it does not look good.

In some places the rivets have worn the chassis rails down to almost half of their original thickness. Also the holes are oval with the outer holes smaller than the inner holes.
The rivets were specified as 13mm in my parts book.
The ones I took out are 14mm in the middle but the holes have worn to 14.8x15.8 on the outer and 15x16.8 on the inner.

The 2 parts can't seperate or be removed from the chassis so I have to repair it where it is.

I will not be using rivets for the repair as I do not have those resources.

Does anyone have an idea on how to repair this?

I tried to inser pics but they came out soo large that I could not see the whole of them. I have converted them to links instead.
















Regards
Bernt

maybe ream the holes until they are round and use Huck bolts (not sure if the spelling is right) if they stand up to boiler work I can't see many problems if using them on your chassis.

However someone with experience in actually fixing a similar problem may have better advice

Hi Berndt, for the pictures just use the IMG code, which is the little picture icon 3rd to the right of URL code you used, make the pictures around 600 X 800 though, yours a little big.

To fix those rivets, weld up the nicks you have left from removing them and flat grind the chassis back then just put bolts in, you can use allen key dome heads if you want them to look original. The little bit it has recessed won't worry it.

Hi
I know about the IMG code but as said, the pics are too big and i can't edit them. None of these new cameras take that low a resolution. In my opnion they were viewable much better links. Right now I an only see a small part of them.

As it stand now, it would need at least an M16 but likely an M20 bolt in there instead of a M14. That is huge and will not look right.

MAN (I think it was MAN but could be Mercedes) specifies that shoulder bolts must be used to repair chassis and that the holes must be reamed to a tight fit.

I guess I can turn up sleeves for the bolts to simulate shoulders but it is the recessing underneath that is the real issue for me. I can weld it up on top but I can't get in underneath.

What I mean is that an M14 or M16 bolt head will only touch the chassis just arond the outer edge if I leave the recess.

Hmm...

Bernt

Unless you are thinking of putting it back to work or loading it the max I wouldn't get too worried about it. You can also weld up around the hole, flat grind it back and re drill it, that will fix the chassis part anyway. If you have plenty of patience you can also put the bolt in the lath a turn the head to look like a rivet.

Really depends on how original you want it too look, how much use it will get and how much time you want to spend.

We used to fill old holes in rails with the punchings or holes done on similar thickness steel from a local steel fabrication shop.

Or if the hole was too small for a hole to be inserted in the hole, clamp a bit of copper behind the hole and fill with weld, bit harder to do on double rails though. After grind the rail flat and start over again with a new bolt hole.

Reaming the hole for a new bolt or rivet is the proper engineering practice and would be good, but how good do you need to have the rails? Your wear around the rivet hole indicates these were loose and rails moved for a while, at least threaded bolts are easier to do up again, Rivets and HUCK bolts you only get once chance of tightening em.

Thanks for the kind suggestions. Greatly appreciated!

Do you mean that your punchings were used as shims / washers to even the rail wear or do you mean they were used as bushes to make the holes round?
Did you weld the punchings into the holes?

The cab bolts to that rail and if it moves around, the cab will break and get damaged again. It was totally gone because of this. It even cracked up the firewall and mudguards where they attach to the cab.

I don't mind it having bolt heads instead of rivet heads as that is purely cosmetic and it all is mostly under the cab.
I will be repairing it properly though as I don't like taking shortcuts that backfire later.


Best regards
Bernt

I've replaced a lot of rivets on the Bedford with high tensile bolts. (make sure you use high tensile washers that won't crush and loosen) In some cases, I had to go the next size up and tidy the hole up with a drill or ream.


Also, the trick to removing rivets is not to use a grinder if possible.

1. Centre punch the dome
2. Drill a pilot hole 3/4 of the way. (don't pop out the back)
3. Drill the dome using a drill a whisker larger than the rivet bore.
4. The head will fall off as it cuts on the edge of the chassis

4a. If your off centre, stop at /near the chassis and use a sharp cold chisel from the edge to tear the head off.

5. With a centre punch, knock out the other half using the pilot hole as the guide.
5a. If its rusted in, drill the out the pilot diameter close to the rivet bore size. (and only 3/4 of the way and then knock it out.)

That way, there is no damage to the chassis and is actually quite easy and fast to do.

Good advise.
I did start by drilling but the rivets just kept spinning and I wasn't able to hold them. I eventually gave up the drilling.

From the second one, I got got better at it and cut the head into a star shape with a 1mm cutting disc.
Then I used a cold chisel to remove the cake slice like sections. The marks you see are purely because I can't see properly. They are unnecessary and I will have to fix them.

Regards
Bernt

jon_d mate every time Ive tried removing truck chassis rivits Ive had no luck the seem to be hammered in that hard that they are expanded out tight against the steel and the only way I can get them out is to cut the top off and then drill through and then blow the rest out with a gas axe maybe I was hitting like a big girly man

big cam theres no need to put bolts in the lathe and turn down for the mushroom head they make high tensile bolts with dome heads for holding points on farm machinery and suppose other things as well if it was me I wouldnt worry if the holes not spot on by an 8.8 bolt do it up with a tension wrench with some big flat washers on each side if you use a nylock nut and fill the holl with bearing retainer it will never move once its set good luck berntd seeya

Paul