Pushing a Daf?.

[banda]

Hi all,


I have somebody coming in two hours to pick up my chassis to take to his garage to have the rebuilt engine installed.


My problem is that the car does not seem to want to roll. Maybe the belts are stuck due lack of use for months?  

Can I force it or drag behind another car on a rope to get it going without damaging anything and if so in neutral or in forward?

Thanks. 

[andrewthe33]

A Daf-ANY Daf should be able to be pushed, pulled or towed without any damage to the transmission or the engine. However, pushing Dafs is harder than pushing a normal car, as you are turning the primary and secondary units as you push, so the rolling resistance is higher. Pushing a 33, 44 and 55 around corners can be particularly hard, as these cars don't have a differential, so that makes it even harder!

Putting the car in neutral will reduce the rolling resistance a little, as the prop shaft and clutch will not then be turning, but this doesn't make much difference. Have the brakes jammed on? Is the handbrake stuck? Jack up the front wheels; both should spin easily and freely. The rear ones should also turn, but this will be harder, but they shouldn't be solidly locked.

Hope this helps!

If it's a VOLVO 66 then there's transmission lock fitted, like the "P" option on ordinary automatics. This will have to be disabled before the car will move.

[banda]

Hi andrewthe33,

A great help thanks. I think the fact that I was getting resistance as compared with the average car alarmed me a little in that I though I might do potential damage if I push too hard.
Armed with your advice I will go back and push harder and also do the checks you recommend. If the brakes have jammed then my mechanic will sort that out at the other end and if I'm not strong enough to beat any resistance I'll drag it out on a rope as the tyres have to be replaced anyway.
Thanks for the great and timely advice.

[starider]

Hi, let us know the result.

[Nick]

This really gets me, never tow a daf in gear, you will spin the clutch drum and prop to ridiculous speeds before the centrifugal change occurs, always tow in neutral, as the prop joints are only rubber.
Killed the prop on the 46 towing it back from bristol, an annoying and expensive mistake. If you think about it when you first start moving a daf the rear pulleys are fully closed so it is effectively in the highest gear it can be. Just my opinion, not moaning or anything

[andrewthe33]

May 15, 2020 18:14:51 GMT Nick said:

This really gets me, never tow a daf in gear, you will spin the clutch drum and prop to ridiculous speeds before the centrifugal change occurs, always tow in neutral, as the prop joints are only rubber.
Killed the prop on the 46 towing it back from bristol, an annoying and expensive mistake. If you think about it when you first start moving a daf the rear pulleys are fully closed so it is effectively in the highest gear it can be. Just my opinion, not moaning or anything

Yes, you're right. When you start towing the transmission is in "low" but you're turning the secondary, which is in the "high" position, so the primary will be spun at a phenomenal speed until the bob weights start to make the primary change up, which would be slower than with the engine, since there would be no vacuum assistance. I should have expected this effect to kick in at about 25-30 M.P.H., after which the transmission would start to change up a little. As regards the speed of the clutch and prop-shaft, I should have thought they would be able to cope with the stresses, providing the towing were kept below 30 M.P.H., as this would be the same as the car being driven at 30 M.P.H. with the low ratio hold energised. The manuals all give 30 M.P.H. as the maximum speed at which the car should be driven with the low hold energised, so towing it withOUT it being energised would mean the transmission would change up to prevent any excessive speeds damaging things. The clutch should be able to cope with speeds up to 4000 R.P.M. without undue stress, as this is regularly reached in normal driving (4000 R.P.M. represents 64 M.P.H. in a Daf 33 in "high" ratio, although I'm not suggesting anyone would be towing at THAT speed....) Engaging neutral would stop the prop and cloth spinning, although the transmission would still be turning.