Parking brake

When applying the parking brake in the unit. Which wheels does the brake apply on?

I know the unit drive axle has the brake on but I always thought the trailer brakes came on too. However today when I had a trailer wheel changed, I noticed that the wheel was spinning on the trailer axle. Could someone clear this up…

Thanks

All different, some lock all six axles, some or used to do just lock drive axle scania used to, dunno about now, some will lock all apart from lift axle.
All depends on the manufacturer.

Depends what chambers are fitted to the steer axle.Single acting chambers dont work off the hand brake but spring brakes do.Your trailer brakes should be applied when you apply the hand valve.
Most tractors with single acting chambers on the front axle are supplied with chocks to stop roll away if you have to jack up the rear axle.

Volvo don’t apply trailer brakes. Every unit is different. For instance a Daf 6x2 applies drive axle only. A Daf 6x4 applied drive and front axle brakes.

Stralis locks the lot up unit and trailer :sunglasses: :sunglasses: :sunglasses:

I prefer ones that just lock the drive axles, they’re better for doing handbrake turns :grimacing:

Anybody know details for scannia??

gurj254:
When applying the parking brake in the unit. Which wheels does the brake apply on?

I know the unit drive axle has the brake on but I always thought the trailer brakes came on too. However today when I had a trailer wheel changed, I noticed that the wheel was spinning on the trailer axle. Could someone clear this up…

Thanks

Possible the fitter had done something like wound the spring off the wheel they were working on, seems like more work than chocks though.

You can check if the unit is putting the trailer brakes on with the unit park brake if you can feel pressure in the yellow line when you couple it.

Very few if any units put on the trailer brakes when park brake is on,trailer brakes work on the secondary position then are let off as you move into park

senior50:
Very few if any units put on the trailer brakes when park brake is on,trailer brakes work on the secondary position then are let off as you move into park

Other way round these days with Swedish makes generally being the ones that don’t but pretty sure some of them do now.

Yep, this is true. Anything with air in the yellow Susie when uncoupling is applying the trailer brakes. Majority of trucks do it now.

gurj254:
Anybody know details for scannia??

Sorry posted first before I saw you’d posted the make. Volvo/Scania probably only on the unit drive axle but wonder if this is changing as had a newish Volvo unit in not long ago and think it might have pressurised the yellow but wasn’t really paying attention. Pretty certain that all other makes I’ve come across do pressurise the yellow line.

Thanks for replies. Seems ours just apply on the drive axle

To supply brakes in a Scania on all axles pull the valve button (PUSH TO SUPPLY) below the handbrake. For Volvo the round know close to the handbrake, iveco? go die :smiley:

Main button when you get stuck on a steep icy hill and risk sliding backwards next to chain throwing…

Icee:
To supply brakes in a Scania on all axles pull the valve button (PUSH TO SUPPLY) below the handbrake. For Volvo the round know close to the handbrake, iveco? go die :smiley:

Main button when you get stuck on a steep icy hill and risk sliding backwards next to chain throwing…

Is the valve button in the cab? Confused

Same here! But Icee appears to be from Finland and perhaps the setup is
different there. :confused:

axletramp:
Same here! But Icee appears to be from Finland and perhaps the setup is
different there. :confused:

He is probably talking about the separate trailer brake handle in the cab, and probably still legal over there.
Was always handy!

weeto:

axletramp:
Same here! But Icee appears to be from Finland and perhaps the setup is
different there. :confused:

He is probably talking about the separate trailer brake handle in the cab, and probably still legal over there.
Was always handy!

I remember the separate trailer brake; it was alongside the parking brake.
Icee is referring to a button below the parking brake and I’ve never seen one.

I think he is talking about the “low pressure popout valve thing” that prevent you from releasing the handbrake if the pressure is too low?

Otoh, when I try that on our scanias, I just rip the button off :frowning: :frowning:

kitbuilder123:
Yep, this is true. Anything with air in the yellow Susie when uncoupling is applying the trailer brakes. Majority of trucks do it now.

And the reason why it’s a good idea to put the yellow line on first!