Is 250 Se-l Auto

[Tango]

Does anyone know what the mechanism is that prevents the auto from rolling back on hills? I did not think mine worked as whenever I stopped it started to roll back, but today I let it continue to roll see what happened and after it rolled back a short distance (less than 12") I heard the mechanism engage and it held position on the hill. Took me three years to find out it worked , but is it transmission or brakes? It sounded like a rear brake mechanism but I really do not know.

The reason I ask is that after using this function, I got a terrible screeching noise from the rear. It is intermittent (every rev of the rear wheels) and sounds like a flapping and rubbing noise. I will be stripping the rear brake assemblies tomorrow to try and locate the source of the noise, but if anyone has any ideas I would appreciate hearing them. It seems more than a coincidence that I got the noise after using the anti roll-back feature of the auto.

I don't think its sticking or seized rear calipers, as both were replaced under warranty at the beginning of December 2008, but I'm also not ruling that out.

[Steve ( West Mids )]

Don't know how it works, but mine holds without rolling back. Not on a very steep gradient but an incline never the less. My drive is very steep and it would just roll back on there and nothing would stop it.

Doesn't answer your question but I don't think it is meant to roll back before it stops the roll. I suspect yours may not be the anti-roll but something in brakes or maybe drive that has developed a fault.

[Parthiban]

From my experience of driving IS250s, the system has always felt identical to the one in my IS200 (could be wrong though) - as Steve says it doesn't roll back and then engage, if it works it just holds the car without rolling back.

The hold thing is definitely the transmission rather than the brakes - although I hope this experience hasn't damaged your transmission in anyway........

[delexus]

From my experience of driving IS250s, the system has always felt identical to the one in my IS200 (could be wrong though) - as Steve says it doesn't roll back and then engage, if it works it just holds the car without rolling back.

The hold thing is definitely the transmission rather than the brakes - although I hope this experience hasn't damaged your transmission in anyway........

Mine will roll back like yours and then hold, then the traction control starts to flash and then it lets go again and repeats this cycle till i give up and put my foot on the brake.

[Tango]

Mine will roll back like yours and then hold, then the traction control starts to flash and then it lets go again and repeats this cycle till i give up and put my foot on the brake.

That's exactly like mine. IMO it's definitely better/easier to use the parking brake.

[Parthiban]

Mine will roll back like yours and then hold, then the traction control starts to flash and then it lets go again and repeats this cycle till i give up and put my foot on the brake.

That's exactly like mine. IMO it's definitely better/easier to use the parking brake.

Definitely trying that out next time I've got an IS250, that sounds bizarre! Dunno why others aren't adding the brake hold function on Mercs that's incredibly useful

[Sagitar]

That's exactly like mine. IMO it's definitely better/easier to use the parking brake.

How do you re-start? Left foot on the parking brake and right foot on the the accellerator? OK, but there is no way of applying the parking brake without locking it. It is difficult to ease it off and balance it as you would with a traditional handbrake.

It's not a frequent problem for me, but I did have real difficulty on the Isle of Wight last year at a junction where the entry road that I was on involved a very steep uphill section and there was busy traffic coming around a sharp bend to the right with limited visibility.

I promised myself afterwards that I would practice the technique required - but of course I haven't :eerrrmm:

[Tango]

That's exactly like mine. IMO it's definitely better/easier to use the parking brake.

How do you re-start? Left foot on the parking brake and right foot on the the accellerator? OK, but there is no way of applying the parking brake without locking it. It is difficult to ease it off and balance it as you would with a traditional handbrake.

It's not a frequent problem for me, but I did have real difficulty on the Isle of Wight last year at a junction where the entry road that I was on involved a very steep uphill section and there was busy traffic coming around a sharp bend to the right with limited visibility.

I promised myself afterwards that I would practice the technique required - but of course I haven't :eerrrmm:

One push locks it, but of course another push unlocks and holds. I find it just as easy to hill start with the left foot on the parking brake as using a handbrake. Press and hold/release with the left foot as you press on the accelerator with the right foot. Simples.