I'm keen to know the outcome of the air pack seals UK manufacturer special order.... Was it successful? My SUMB has exactly the same symptoms as described by 21BK40. All looks good on the air pressure but brake pedal needs a hell of a heavy boot with no apparent air assistance kicking in. I haven't yet checked if the air pack is getting the necessary hydraulic "signal" via the master cylinder, but I suspect that the air pack isn't operating properly and it is either 'sticky' and needs cleaning out or needs new seals. If you are still out there 21BK40, how did your story finish? MUDMAX Mike
Good afternoon everyone, I'm Mike, and I thought I'd indroduce myself as a new member of HMVF...Today I bought a 1959 SIMCA MARMON SUMB 4x4 French military truck and I'm quite excited. (Pic attached) I am new to the French military truck world but have been fiddling with Land Rovers and particularly V8 Range Rover Classics for years, so not scared of working on chunky metal stuff with oil leaks. The truck been very well looked after by the previous owners, with everything looking clean and tidy. I guess it's been parked up for a while and as you might expect, the air brakes aren't performing at all well so it is being delivered to me on the back of a recovery truck tomorrow as the current keeper is too scared to drive it. I guess it's a dodgy valve or some seals that need sorting out, but never worked on an air system before so advice and opinions on the cause and suggested repairs are most welcome. Symptoms: Air pressure up at 9-10bar which I think is normal. The system "blows off" excess air pressure every few minutes which I think is also normal. The bad stuff: Brake pedal rock hard so you need to press really hard to get any braking at all. Once the pedal moves down the brakes kick in and bite well. It seems as though the air assistance is not there at all and the pedal has to be forced down to a point where the hydraulics eventually do their thing and stop the truck. I don't mind if I fix it myself or pay a local air brake expert. Braking is quite important to get right, so if you can help with any advice or recommendations I would be most grateful. MUDMAX MIKE - Solihull, West Midlands.
Hello... Just joined HMVF as I have just become the proud owner of a 1959 Simca Marmon SUMB. It arrives tomorrow on the back of a recovery wagon. Don't know much about it yet, other than the air brakes aren't working properly. I've been reading your thread of a few years ago about air brakes. My motor has exactly the same symptoms: Pleanty of air pressure, the guage reads 10Bar, but rock hard pedal and no braking action until you push through the hard pedal and stand on it, then the brakes bite hard!... I suspect the air pack seals.
Did you solve your air brakes problem?
Any advice would be very gratefully received.
MUDMAX Mike - Solihull, West Midlands.