Parking in Gear
Discussion
Should parking with the Cerb in first gear pretty much hold it on any slope?
Just bought some of those restoration-ramps to get access underneath, to get on them you have to go up quite a steep incline. Handbrake wasn't going to hold it and the first couple of times (with the engine cold) putting it in gear held it while I got out and levelled the ramps. Sunday night, got back from a 140 mile blast, drove up ramps and the car wouldn't stay still even when in gear! Could this be a lack of compression or a slipping clutch?
Just bought some of those restoration-ramps to get access underneath, to get on them you have to go up quite a steep incline. Handbrake wasn't going to hold it and the first couple of times (with the engine cold) putting it in gear held it while I got out and levelled the ramps. Sunday night, got back from a 140 mile blast, drove up ramps and the car wouldn't stay still even when in gear! Could this be a lack of compression or a slipping clutch?
brooksie said:
am i missing something guys ? .. why not use the handbrake ? .. mine seems to work ok ? (for general use, obviously not tried it on a ramp !)
Because if you think of the way it works you will see that if you use it while stationary one day it will let you down.
If you use it while driving you are letting the car down, and possibly the entire race of mankind while you slowly change into a woman.
.. who on earth drives with their handbrake on ? 
Julian64 said:
brooksie said:
am i missing something guys ? .. why not use the handbrake ? .. mine seems to work ok ? (for general use, obviously not tried it on a ramp !)
Because if you think of the way it works you will see that if you use it while stationary one day it will let you down.
If you use it while driving you are letting the car down, and possibly the entire race of mankind while you slowly change into a woman.
The Cerb uses a handbrake system like many other cars, it has rear discs that have an itegral drum for the handbrake shoes, the shoes are operated by a cable that in turn is operated by the lever. So if properly adjusted it should work fine! One thing you can do to assist the handbrake is to apply in whilst driving! Not to the extreme though, the internal surface of the drum can rust up so if you apply whilst driving in a controlled manor then you use the shoes to clean the drum! I used to do this in my Cav GSI many years ago, then i found out that it was actually in the owners hand book! I believe that the main problem is the position of the lever, it is hard do give it a good tug
. The thinking behind the failing handbreak is this:
If you have been driving quite hard and breaking the same then the brake discs expand due to the heat generated. You then stop, put the handbrake on (with expanded discs) and leave the car (to cool down). The discs then cool reducing in size but the handbrake shoes dont move so that their grip is reduced causing the car to roll down the nearest hill!
Thats how it was explained to me anyways BUT..........
I see it in a different way,
The shoes are inside a drum (that is also the disc), when the drum gets hot it expands (its internal diameter increases), so if you apply the handbrake at this point then this is the maximum size the drum can ever be! When the drum cools down then it shrinks pushing against the shoes! Therfore increasing its grip!
So what do you all think? Am i correct or the bloke down the pub? Does anyone know the actual reason for the poor handbrake on the cerb?
And No, the cerb is not on a conveyor belt
Edited by headcase on Wednesday 21st February 18:51
Dunno but I was happily using the handbrake until we were on the ferry to the Isle of Wight. The nice ferryman put us on right at the front on our own, but on the upper ramp. When we got to the otherside I had to jab my foot on the brake quickly as he let the ramp down with us on it.
headcase said:
BUT..........
I see it in a different way,
The shoes are inside a drum (that is also the disc), when the drum gets hot it expands (its internal diameter increases), so if you apply the handbrake at this point then this is the maximum size the drum can ever be! When the drum cools down then it shrinks pushing against the shoes! Therfore increasing its grip!
So what do you all think? Am i correct or the bloke down the pub? Does anyone know the actual reason for the poor handbrake on the cerb?
I see it in a different way,
The shoes are inside a drum (that is also the disc), when the drum gets hot it expands (its internal diameter increases), so if you apply the handbrake at this point then this is the maximum size the drum can ever be! When the drum cools down then it shrinks pushing against the shoes! Therfore increasing its grip!
So what do you all think? Am i correct or the bloke down the pub? Does anyone know the actual reason for the poor handbrake on the cerb?
I reckon you're right headcase, exactly what I was thinking.
jensena said:
headcase said:
BUT..........
I see it in a different way,
The shoes are inside a drum (that is also the disc), when the drum gets hot it expands (its internal diameter increases), so if you apply the handbrake at this point then this is the maximum size the drum can ever be! When the drum cools down then it shrinks pushing against the shoes! Therfore increasing its grip!
So what do you all think? Am i correct or the bloke down the pub? Does anyone know the actual reason for the poor handbrake on the cerb?
I see it in a different way,
The shoes are inside a drum (that is also the disc), when the drum gets hot it expands (its internal diameter increases), so if you apply the handbrake at this point then this is the maximum size the drum can ever be! When the drum cools down then it shrinks pushing against the shoes! Therfore increasing its grip!
So what do you all think? Am i correct or the bloke down the pub? Does anyone know the actual reason for the poor handbrake on the cerb?
I reckon you're right headcase, exactly what I was thinking.
Don't think so. amecdotally you should be looking for a reason for them doing the opposite.
Although your science seems correct, I believe your emphasis is wrong. The culprit is the stretch in the cable, or the loss of hydraulic pressure if you happen to have a hydraulic handbrake.
Metal cables stretch with constant strain. Which allied with brake shoe wear is why you have an adjuster on the handbrake lever in the first place.
I would venture to guess its the cam which forces your brake shoes apart which slowly but gently releases its pressure on the brake shoes.
Julian64 said:
jensena said:
headcase said:
BUT..........
I see it in a different way,
The shoes are inside a drum (that is also the disc), when the drum gets hot it expands (its internal diameter increases), so if you apply the handbrake at this point then this is the maximum size the drum can ever be! When the drum cools down then it shrinks pushing against the shoes! Therfore increasing its grip!
So what do you all think? Am i correct or the bloke down the pub? Does anyone know the actual reason for the poor handbrake on the cerb?
I see it in a different way,
The shoes are inside a drum (that is also the disc), when the drum gets hot it expands (its internal diameter increases), so if you apply the handbrake at this point then this is the maximum size the drum can ever be! When the drum cools down then it shrinks pushing against the shoes! Therfore increasing its grip!
So what do you all think? Am i correct or the bloke down the pub? Does anyone know the actual reason for the poor handbrake on the cerb?
I reckon you're right headcase, exactly what I was thinking.
Don't think so. amecdotally you should be looking for a reason for them doing the opposite.
Although your science seems correct, I believe your emphasis is wrong. The culprit is the stretch in the cable, or the loss of hydraulic pressure if you happen to have a hydraulic handbrake.
Metal cables stretch with constant strain. Which allied with brake shoe wear is why you have an adjuster on the handbrake lever in the first place.
I would venture to guess its the cam which forces your brake shoes apart which slowly but gently releases its pressure on the brake shoes.
Yep, you have a valid point there, this would accout for the handbrake lever getting progressivly higher with time, but i dont think it could be the cause of it being ok when you put it on then 30mins later the car rolls down the hill!
Does this fault actually happen? Or is it the general scaremongering making up additional faults, i think maybe it could be a badly adjusted brake that just about holds then gives up some time later!
This system is quite a good one that is used in many cars other that the cerb and it dosent seem to give many problems there apart form siezing on when its icy!
jensena said:
Me and Headcase are talking about this 'Dont use the handbrake because when the brakes cool the handbrake fails' myth.
Just as an side, this was a documented fault with early Citroen Xantias. Handbrake worked on the front discs which then contracted followed by bye-bye car. It got reported on the TV some years back.
Gassing Station | Cerbera | Top of Page | What's New | My Stuff