now thats funny! that pic above is my blue 340 that I dismantled!!

There is an internal brace inside the chassis which traps water and needs to be bone dry if you inject rustproofing fluid. I foun it by poking a wire frm the holes inside the boot(covered by soundproofing)

Just edited so the image displays...

thanks for the update!

my friend used to make Y shaped pieces for this chassic repair as this was a common repair when the 340s were still popular and 'worth' fixing

I say worth as according to him now, the repair exceeds the cars worth and takes too long to do. I tried, but he isnt interested in making these units for the club. He's soon to retire and is too busy with other things.


However, thats a new line of things we could do if someone is gifted at sheet metal fab. Sometimes just a L shape is need to repair but to go 'all out' would be to fit the Y shape piece.

what also adds to the cost at garages is removal of the tank which means from start to finish its a full day for a garage which too adds to the cost

however, being a 300 club, I think guys here could do it to prevent MOT failure. The back of the sills is a harder repair....

all the best

I wonder if your retired welding friend used repair plates approved by Volvo if he worked for a main dealer ? I cant see why you need "Y" shapes rather than "T" shapes . Perhaps you could try and get the drawings from him. It is quite easy to cut 1mm sheet steel even with hand shears. Dropping the tank is quite easy on the 340 and you could drive to the welders using a petrol can in the boot as a temporary tank.

regards, Steve

Not knowing exactly what the 340 tank looks like from memory, compared to the 360 tank, there's no need to drop the tank on a 360, (thankfully!) just remove the filler pipe, then cap off the tank, and make sure it's low on fuel to start with.

Just looked in Haynes, it seems at though the 340 tank isn't too much different to the wheel well on a 360, but fits the rear axle a bit tighter and follows it's shape. Although it's tight on the O/S, it can't be too much tighter than a 360, and my Uncle managed that.

Pete.

I've finally found the picture I was thinking of regarding srtames's post.



That show's quite a lot of festering rust in the area you pointed out near that join. That car sat for a long time, so the condensation would collect in there. A car that gets a fair bit of use, the heat from the engine bay should help dry that out a bit I'd have thought. Dinitrol ftw!

Pete

Right, I've finally got the pictures I wanted of the chassis rails. Srtames is spot on about the bracing inside the rear rails near where it normally rusts near the tank, then resulting in an MOT failure. Being the sort of person I am, and having a shell going for scrap, I took to it with the angle grinder to illustrate to everyone exactly what it looks like and as curiousity got the better of me! Oddly, this car had perfect chassis rails, yet had rust in other places that meant it wasn't fantastic and worth saving.

*Note, any rusty looking deposits are actually metal shards from the grinding, the inside of the rails were super clean on this car, and showed signs of waxoyl in places.*

The bracing inside the rails. (Facing the rear of the car.)

Section near the crossrail near the T join to the chassis rails.

Showing both, just, top of picture for the straighter one.

Note missing wheelwell........Dai! Anyway, this also shows the cross piece of the rail over the tank. This has taught me that inorder to get any rust prevention into the section trapped by the braces or sidewalls you need to spray from down between the two threaded pieces either side of the circle, which if I'm remembering rightly is a removable grommet.


Anyway, pictures paint a thousand words, so I hope that these will help other in the rust prevention process and the understanding of the problems. I've a couple more pictures to post in a new thread one day of the A pillar section by the front doors and also the inner wings towards the door hinge area, where there is an extra inner section of metal to make matters worse!

Right, start buying rust prevention treatments, Dinitrol is my recommended choice!

Pete

very illuminating pictures of the cross braces in the chassis rails . There looked like rust around the bottom flange weld of the straight brace which is the other side of the T piece underneath so making a nice double sandwich for rust to fester in unseen! Worth adding to a sticky for rustproofing/ welding tips

regards, Steve

Exactly Steve, often by the time it gets to the outside layer, it's though and everything is rotted away! Either MOT failure or time for major welding!

I'll remember to put it in a sticky or a how to guide at some point.

Pete