scootz
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| posted on 28/7/16 at 06:19 PM |
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Handbrake Operation
Daft question time... I get how a typical handbrake system pushes the inner pistons out.
But how do the pistons retract once you've let the handbrake off? Is it just a case of the hydraulic system pulling them back?
Reason I'm asking is that I was going to use a pair of handbrake calipers as a handbrake only device to save on buying spot-calibers and new
cables, but then it occurred to me, "will I need to retain some brake fluid in the caliper"!?
It's Evolution Baby!
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britishtrident
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| posted on 28/7/16 at 06:27 PM |
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Exactly as in hydraulic operation it is all done by the distortion of the inner seal,
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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scootz
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| posted on 28/7/16 at 07:54 PM |
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Thanks for that.
Any recommendations on how to make it 'handbrake only' function?
It's Evolution Baby!
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gremlin1234
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| posted on 28/7/16 at 10:48 PM |
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any, and all run-out of the disk will knock the pads back far enough that they clear the disk. -just don't make it too perfect ;-)
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Slimy38
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| posted on 29/7/16 at 07:25 AM |
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If I am understanding this, you want to run the calipers 'dry', or at least not feed them with fluid? If so I'm not sure it will
work. At the very least it won't be able to compensate for pad wear. Even just filling them from a short length of terminated brake pipe will
not give you the wear characteristics required. Eventually the handbrake will stop working.
Is there no cost effective handbrake only caliper?
Edit: Actually, thinking about it, if you do seal it, as long as the mechanical action can overcome the vacuum, then the vacuum would do the
retraction. Maybe have a little bit of brake fluid in there for seal lubrication but keep it mostly air? Would that do what you're after?
[Edited on 29/7/16 by Slimy38]
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JAG
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| posted on 29/7/16 at 07:40 AM |
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quote:
Eventually the handbrake will stop working
Not true - the handbrake lever will travel further as the pads wear but it won't stop working. Pads won't wear very quickly so long as you
only use it for Parking. It may eventually need adjusting but I'm sure you can manage that.
You should also put some brake fluid inside the caliper as the handbrake mechanism and the seal rely upon the brake fluid for lubrication. On road
cars with handbrake only calipers we put 10 ml of brake fluid inside.
Cars like this;
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
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Slimy38
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| posted on 29/7/16 at 08:00 AM |
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quote:
Originally posted by JAG
Not true - the handbrake lever will travel further as the pads wear but it won't stop working. Pads won't wear very quickly so long as you
only use it for Parking. It may eventually need adjusting but I'm sure you can manage that.
Good point, thinking about it handbrake pads (in theory) shouldn't wear at all if they're just used to hold the vehicle.
(edit: Nice pic by the way!  )
[Edited on 29/7/16 by Slimy38]
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micksalt
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| posted on 29/7/16 at 09:03 AM |
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Is it not an awful lot of extra unsprung weight to use a combination caliper compared to a dedicated spot?
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JAG
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| posted on 29/7/16 at 02:15 PM |
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Not really - when you do have a handbrake only caliper on a production car it's usually teamed with an opposed piston caliper. The opposed
piston caliper is Aluminium and lighter so it offsets the extra handbrake caliper.
On the Jaguar we also have the weight saving of the Carbon-Ceramic disc which is only 5.3 kg compared to an equivalent Iron disc around 12 kg.
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
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