Is it possible to stop an A2 with no working servo?

Alan_uk

Alan_uk

A2OC Donor
I was passing though Bradford on Avon (near Bath) today; a small historic town suffering from traffic and pollution** (made worse lately by an alternative route that has been closed for months). So trying to minimise my A2 diesel fumes I turned my engine off, (as I do in queues, traffic lights etc), and then decided to roll forward on a rather steep hill. Panic! A2 was very difficult to stop and I quickly pulled on the handbreak and restarted it.

Made me think, what happens if the servo suddenly fails. Would it be near impossible to stop it in a reasonable distance?

The last time I was towed on a rope was 25+ years ago (not an A2 but a Cavalier) and I remember how hard that was to brake. Are recovery vehicles (or anyone) no longer allowed to tow on a rope?

** there is a pollution monitoring unit often reaching the permitted limits at certain hours, particularly NO2.
 
My one experience of being towed was 4 years ago by a RAC van, not using rope but a metal tube kit. The RAC van did my braking, all I had to do was steer and that like brakes took a bit of effort without any engine assistance, you forget the days before PAS we all must have had bigger biceps then.

Andy
 
After being towed on a rope for 20 miles, you need to pump the brakes hard, they do work, but pressure is needed to be built first, then pressing very hard for breaking


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Brakes without servos have pistons sized to give operating pressures and piston travel without assistance. Without vac a servo braking system cannot default to a non assisted system so much much more effort is needed, even before any complications of the ABS are considered.
 
Andrew said:
My one experience of being towed was 4 years ago by a RAC van, not using rope but a metal tube kit. The RAC van did my braking, all I had to do was steer and that like brakes took a bit of effort without any engine assistance, you forget the days before PAS we all must have had bigger biceps then.

Andy
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I’m about to put a non PAS car back on the road after an extensive 5 year tidy up. From memory you need biceps to park it but the steering has better feel than PAS once moving. It doesn’t feel heavy at all on the move.
 
philward said:
Brakes without servos have pistons sized to give operating pressures and piston travel without assistance. Without vac a servo braking system cannot default to a non assisted system so much much more effort is needed, even before any complications of the ABS are considered.
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Similarly cars designed without PAS tend to have larger steering wheels and lower geared racks (more turns lock-to-lock) to help you. My 1993 campervan without PAS is a bit of a beast at manoeuvring speeds but it's fine once you're on the move, even in traffic.
 
Proghound said:
Similarly cars designed without PAS tend to have larger steering wheels and lower geared racks (more turns lock-to-lock) to help you.
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and skinnier tyres!

Proghound said:
My 1993 campervan without PAS is a bit of a beast at manoeuvring speeds but it's fine once you're on the move, even in traffic.
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Early T4, by any chance? We had a '92 one without PAS and it was hard work parking, but fine on the move. Great big steering wheel though!
 
gills said:
Early T4, by any chance? We had a '92 one without PAS and it was hard work parking, but fine on the move. Great big steering wheel though!
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Nope, it's one of the last year of production of the Talbot Express - the last model ever to bear the Talbot name, although it was actually just a re-badged version of the 1st-generation PSA/Fiat van for the UK market.
 
We went on to a Boxer based van, which was basically just an updated Express (with PAS and a dash-mounted gearlever!)
 
Alan_uk said:
I was passing though Bradford on Avon (near Bath) today; a small historic town suffering from traffic and pollution** (made worse lately by an alternative route that has been closed for months). So trying to minimise my A2 diesel fumes I turned my engine off, (as I do in queues, traffic lights etc), and then decided to roll forward on a rather steep hill. Panic! A2 was very difficult to stop and I quickly pulled on the handbreak and restarted it.
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Alan, you should have done nothing except take your foot off the accelerator. On overrun, a PD diesel will not inject any fuel!

RAB
 
RAB said:
Alan, you should have done nothing except take your foot off the accelerator. On overrun, a PD diesel will not inject any fuel!

RAB
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Hi RAB. As the engine was off I'm sure I was in neutral. So maybe putting into gear would have worked. I don't think it is good to stall a running engine.
 
No, what RAB is saying is leave the engine running and the car in a low gear. When you lift off the throttle known as "overrun" the computer shuts off the fuel supply and this increases the engine braking effect. Not engine switched off and leave the car in gear.

Engine running you still have full control of both the brakes and the steering. Coasting on the other hand provides no engine breaking, still uses fuel and is also illegal...
 
audifan said:
No, what RAB is saying is leave the engine running and the car in a low gear. When you lift off the throttle known as "overrun" the computer shuts off the fuel supply and this increases the engine braking effect. Not engine switched off and leave the car in gear.

Engine running you still have full control of both the brakes and the steering. Coasting on the other hand provides no engine breaking, still uses fuel and is also illegal...
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A lot of new cars do this automatically these days.

www.pistonheads.com

What is a 'coasting' function? PH Explains

The concept of coasting to save fuel isn't a new one but automated systems take things one step further
www.pistonheads.com www.pistonheads.com


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