Lotus Elan

Caliper Rebuild

PostPost by: s2lola » Wed Mar 23, 2005 2:13 pm

Baloney indeed. Fair enough. I rescind my recommendation to never use
compressed air to remove a sticky caliper piston. Far be it from me to
suggest a way in which, assuming an Elan owner does a thorough strip and
clean (of the caliper bits, get your minds out of the gutter) afterward, can
not injure him/herself.

We should encourage more daring-do on this list. The scuba tank is a great
idea - the more pressure the better (I think it was said 2000psi, vs my home
shop compressor of a measely 125psi). For laughs, can one of the
not-mathematically-challenged engineers on this list calcualte the parting
velocity of a freed caliper piston with 2000psi behind it, and also
calculate how far it might travel before landing? And while I'm at it, I
think I'll....
- Run with scissors
- Smoke at the filling station
- Light the BBQ with the lid closed
- Ride my motorcycle with no helmet
- Drive the car without seatbelts
- Carry our infant in the front seat
- Remove all eye protection from the workshop.

Ah, the zen-like freedom of a careless existance...................

Bill





-----Original Message-----
From: e s [mailto:***@***.***
Sent: 2005/03/22 20:14
To: ***@***.***
Subject: Re: [LotusElan.net] Caliper Rebuild



Bunch of baloney.

Did this myself, biggest problem is that once one piston comes out it has to
be held in place to get the other out. If a caliper were to come apart
during this process, it would be have been very dangerous in service, as the
brake pressure can get that high. Other than that there is no danger, the
pistons CANNOT shoot anywhere.
----- Original Message -----
From: "Martin Evans" <***@***.***>
To: ***@***.***
Subject: Re: [LotusElan.net] Caliper Rebuild
Date: Tue, 22 Mar 2005 22:03:05 +0000


On Wed, 23 Mar 2005 08:18:50 +1100, <***@***.***> wrote:

> Never Ever used compressed gas to remove anything that is stuck
> it is VERY dangerous. Always use a fluid like oil or grease.
>
> Just think of how an air rifle would work if it used oil instead
> of compressed air and you should get the picture.
>
> And if you do use compressed air on your caliper dont point oi at
> anyone, including yourself.

I'd always use grease with a troublesome piston followed by a full
strip and degrease rather than ever letting compressed air near a
caliper - but in the past few days AP (suppliers of the Elise front
calipers) have published a procedure for caliper overhaul that says
use compressed air.

http://www.apracing.com/roadcar/caliper/calservice1.htm


Martin

72/45
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s2lola
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PostPost by: "Stan Aarhus" » Wed Mar 23, 2005 2:25 pm

I used the "reaction block" technique the last time I rebuild my calipers. In my case it is a piece of white oak cut to fit. In applying the air, just hold he nozzle near, not on, the bleeder screw. Between the nozzle trigger and varying the distance from the bleeder screw you get a relatively low pressure. If it doesn't move right away, I hold it at that level for a bit and wait. Don't be in a big hurry to increase the pressure. Moderate air pressure and patience have worked for me. I haven't tried it yet, but Iwould guess that a pressure regulator would be good to help maintain the low pressure.

Cheers!

Stan
----- Original Message -----
From: rob_lamoreaux
To: ***@***.*** ; 'Martin Evans'
Sent: Wednesday, March 23, 2005 6:33 AM
Subject: RE: [LotusElan.net] Caliper Rebuild


I'd always use grease with a troublesome piston followed by a full
strip and degrease rather than ever letting compressed air near a
caliper - but in the past few days AP (suppliers of the Elise front
calipers) have published a procedure for caliper overhaul that says
use compressed air.

http://www.apracing.com/roadcar/caliper/calservice1.htm



I do note that AP says "a perfect seal between the air gun and fitting is
neither necessary or advisable". They are using low pressure air on the
pistons so they do not explode out and damage themselves against the
"reaction block".

Compressed air will continue to expand after the piston comes loose, where
an uncompressible liquid will stop expanding when the piston begins to move.
One of the best ways to move the piston is an hydraulic pump and hydraulic
fluid including the master cylinder of the car.

Rob LaMoreaux
Ann Arbor, MI USA
(734)-971-5583
Cell (734)-604-9280
Email: ***@***.***
Too many Hobbies.... Too Little Time
1969 Lotus Elan....It's not a restoration, it's a never-ending adventure.











To search the mailing list archives:
http://www.escribe.com/automotive/europ ... index.html
"Stan Aarhus"
 

PostPost by: steveww » Wed Mar 23, 2005 5:33 pm

Eye protection in the workshop? Whats that then? I just close my eyes
when using the angle grinder ;-)

Bill Tebbutt wrote:
Baloney indeed. Fair enough. I rescind my recommendation to never use
compressed air to remove a sticky caliper piston. Far be it from me to
suggest a way in which, assuming an Elan owner does a thorough strip and
clean (of the caliper bits, get your minds out of the gutter) afterward, can
not injure him/herself.

We should encourage more daring-do on this list. The scuba tank is a great
idea - the more pressure the better (I think it was said 2000psi, vs my home
shop compressor of a measely 125psi). For laughs, can one of the
not-mathematically-challenged engineers on this list calcualte the parting
velocity of a freed caliper piston with 2000psi behind it, and also
calculate how far it might travel before landing? And while I'm at it, I
think I'll....
- Run with scissors
- Smoke at the filling station
- Light the BBQ with the lid closed
- Ride my motorcycle with no helmet
- Drive the car without seatbelts
- Carry our infant in the front seat
- Remove all eye protection from the workshop.

Ah, the zen-like freedom of a careless existance...................

Bill





-----Original Message-----
From: e s [mailto:***@***.***
Sent: 2005/03/22 20:14
To: ***@***.***
Subject: Re: [LotusElan.net] Caliper Rebuild



Bunch of baloney.

Did this myself, biggest problem is that once one piston comes out it has to
be held in place to get the other out. If a caliper were to come apart
during this process, it would be have been very dangerous in service, as the
brake pressure can get that high. Other than that there is no danger, the
pistons CANNOT shoot anywhere.
----- Original Message -----
From: "Martin Evans" <***@***.***>
To: ***@***.***
Subject: Re: [LotusElan.net] Caliper Rebuild
Date: Tue, 22 Mar 2005 22:03:05 +0000


>On Wed, 23 Mar 2005 08:18:50 +1100, <***@***.***> wrote:
>
>
>>Never Ever used compressed gas to remove anything that is stuck
>>it is VERY dangerous. Always use a fluid like oil or grease.
>>
>>Just think of how an air rifle would work if it used oil instead
>>of compressed air and you should get the picture.
>>
>>And if you do use compressed air on your caliper dont point oi at
>>anyone, including yourself.
>
>I'd always use grease with a troublesome piston followed by a full
>strip and degrease rather than ever letting compressed air near a
>caliper - but in the past few days AP (suppliers of the Elise front
>calipers) have published a procedure for caliper overhaul that says
>use compressed air.
>
>http://www.apracing.com/roadcar/caliper/calservice1.htm
>
>
>Martin
>
>72/45
>--



--

Regards,

Steve Waterworth
***@***.***

Einstein: "The faster you drive, the slower you age..."
User avatar
steveww
Coveted Fifth Gear
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Posts: 1838
Joined: 18 Sep 2003
Location: Northamptonshire, England

PostPost by: s2lola » Wed Mar 23, 2005 7:40 pm

Me too. Call me Lefty......

-----Original Message-----
From: Steve Waterworth [mailto:***@***.***
Sent: 2005/03/23 12:33
To: ***@***.***
Subject: Re: [LotusElan.net] Caliper Rebuild



Eye protection in the workshop? Whats that then? I just close my eyes
when using the angle grinder ;-)

Bill Tebbutt wrote:
Baloney indeed. Fair enough. I rescind my recommendation to never
use compressed air to remove a sticky caliper piston. Far be it from
me to suggest a way in which, assuming an Elan owner does a thorough
strip and clean (of the caliper bits, get your minds out of the
gutter) afterward, can not injure him/herself.

We should encourage more daring-do on this list. The scuba tank is a
great idea - the more pressure the better (I think it was said
2000psi, vs my home shop compressor of a measely 125psi). For laughs,
can one of the not-mathematically-challenged engineers on this list
calcualte the parting velocity of a freed caliper piston with 2000psi
behind it, and also calculate how far it might travel before landing?
And while I'm at it, I think I'll....
- Run with scissors
- Smoke at the filling station
- Light the BBQ with the lid closed
- Ride my motorcycle with no helmet
- Drive the car without seatbelts
- Carry our infant in the front seat
- Remove all eye protection from the workshop.

Ah, the zen-like freedom of a careless existance...................

Bill





-----Original Message-----
From: e s [mailto:***@***.***
Sent: 2005/03/22 20:14
To: ***@***.***
Subject: Re: [LotusElan.net] Caliper Rebuild



Bunch of baloney.

Did this myself, biggest problem is that once one piston comes out it
has to be held in place to get the other out. If a caliper were to
come apart during this process, it would be have been very dangerous
in service, as the brake pressure can get that high. Other than that
there is no danger, the pistons CANNOT shoot anywhere.
----- Original Message -----
From: "Martin Evans" <***@***.***>
To: ***@***.***
Subject: Re: [LotusElan.net] Caliper Rebuild
Date: Tue, 22 Mar 2005 22:03:05 +0000


>On Wed, 23 Mar 2005 08:18:50 +1100, <***@***.***> wrote:
>
>
>>Never Ever used compressed gas to remove anything that is stuck it is
>>VERY dangerous. Always use a fluid like oil or grease.
>>
>>Just think of how an air rifle would work if it used oil instead of
>>compressed air and you should get the picture.
>>
>>And if you do use compressed air on your caliper dont point oi at
>>anyone, including yourself.
>
>I'd always use grease with a troublesome piston followed by a full
>strip and degrease rather than ever letting compressed air near a
>caliper - but in the past few days AP (suppliers of the Elise front
>calipers) have published a procedure for caliper overhaul that says
>use compressed air.
>
>http://www.apracing.com/roadcar/caliper/calservice1.htm
>
>
>Martin
>
>72/45
>--



--

Regards,

Steve Waterworth
***@***.***

Einstein: "The faster you drive, the slower you age..."






To search the mailing list archives:
http://www.escribe.com/automotive/europ ... index.html

Copyright(c) LotusElan.net and the author:

Yahoo! Groups Links








***********************************************************************************
Financiere Banque Nationale et NBCN n'assument aucune responsabilite quant a la confidentialite et l'integrite du present courriel en raison des risques d'interception inherents a l'Internet. Pour cette raison, toute opinion exprimee au terme des presentes ne reflete pas necessairement celle de Financiere Banque Nationale et de NBCN.
***********************************************************************************
Due to the security risks involved in sending information over the Internet, National Bank Financial and NBCN can not be held
responsible for ensuring the confidentiality and integrity of the present e-mail. For this reason, the opinions expressed herein do not
necessarily reflect those of National Bank Financial and NBCN.
***********************************************************************************
s2lola
Third Gear
Third Gear
 
Posts: 260
Joined: 16 Jan 2004
Location: Toronto, Ontario
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