So, im doin a suspension project at uni, naturally im going to do it on my volvo. It just got me wondering, anyone know the standard spring rate for the 340 series, and why did DAF/Volvo decide to go for leaf springs on the back.

Also, an engine question. Theres an oil line going from the engine to the carb, to the bulk head. I was going to put a catch tank from the rocker cover to the tank, this would however get rid of the line to the carb and bulk head. What are those lines for? just recirculation? Im going to take a picture of the line that i mean anyway, but i dont want to have a pipe to the catch tank, and realise the line is something important for the carb.

If it's a fabric covered one then it's a fuel return hose.

There are no external oil lines I am aware of in any 300, something more associated with turbos. Probably breathers, to create a partial vacuum in the crank case.

I always thought It had leaf springs becuase it was designed in the 70's and leaf springs are very cheap. Perhaps its also to do with the RWD setup where a chapman/McPherson strut setup is more difficult to combine with drive shafts.

Yeah, its definatly not fuel. It must be what Ride_on said. It comes from the little plastic T-piece off the rocker cover, via tube to the carb, hence why i thought recirculation/breather. Still dont know whether removing this would do anything detrimental. More weber carb research is needed. I'll grab a pic tomorrow of what i mean.

mrsoundcraft wrote:I always thought It had leaf springs becuase it was designed in the 70's and leaf springs are very cheap. Perhaps its also to do with the RWD setup where a chapman/McPherson strut setup is more difficult to combine with drive shafts.

Makes sense!

It's a breather.

The one that leads to and from the carb. The same tube goes to the bulkhead too, but why?





Its got to be a breather, like evryones said, but why lead back through the bulkhead?

That looks like the speedo cable going through the bulkhead. The other tubes appear to be vacuum.

it's not a breather. it's for your economy gauge, top left of your clockset.

and someone has been messing about with your breather pipes and this is a very, very wrong setup

the hose coming from the actual breather vent in the valve-cover is kinked; hence you can get overpressure in the engine wich will make it throw out the oil on every seal.
this kinked hose is ment to go to a connection on the airfilter housing, normally there's a connecting T-piece where the thinner hose connects to. the thinner hose, going to the base of the carb should have a restrictor in it with a hole of about 1mm in diameter.

it looks like both these hoses have been replaced, and since the smaller one is routed underneath the fuel-feed i can't see if this restrictor is still in place. if it's gone, your engine is running rough and is NOT properly tuned.
but before that, make sure you get the kink out of that hose from the breather first or you'll have a lot more work than you would've want to... if you're fitting a catch-tank in the end, then use the connection on the base of the carb only for the hose that goes through your bulkhead to the econometer, and throw away the bit that goes to the breather.

That er, someone, would be me. I snapped the plastic T-piece, looked under the air filter to where the hose origional went (kinked one) and it went no where. so i bodged, and used the hose to join them together, not knowing how important it was. I'll fit the catch tank before i drive it again. Im so embarassed about that. what a tit.

The hose that is kinked always was kinked (before t-peice breakage), and with the re routing, it seemed to work and i didnt think much of it.

Thanks for that response lad. I'll inspect the line for the restrictor. apart from the t-piece, ive never taken anything off, so it should still be there.

Leaf spring design was probably just a DAF heritage which Volvo didn't see productive to change. Volvo 343/345 was a DAF 77 on the drawing board before Volvo bought the design. Volvo Amazon has coils (and in same manner Volvo 140 had disc brakes at the rear as stock) at the back so it hasn't got that much to do with the age. DAF just had different design and not so advanced. (drum brakes, leafs etc..)



Though leafs work surprisingly well at the rear with the DeDion axle. Not nearly as bad as it would be with conventional live axle as there's kess unsprung weight and the drive train is not supported by the leafs.

-Marko