|
|
| Author |
Message |
Nick.S.
Joined: 08 Nov 2011
Posts: 64
Location: Manitoba, Canada.
|
 Posted: Fri Dec 09, 2011 7:08 pm Post subject: casting rubber, what kind? |
 |
|
hello,in rebuilding my Austin A40 i have come across several rubber parts that need replacing as the original rubber has turned to goo. these items include the engine and transmission mounting blocks, boots for the brakes, boots for the brake and clutch pedals, as well as a few gaskets and seals. some i have found on ebay, but some like the brake master cylinder seals, i cant find at all. for these i was wondering about casting rubber
http://www.ebay.ca/itm/120561315312?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649#ht_1464wt_1204
this is a castable rubber i found, would it hold up to brake fluid?
any info would be very helpfull, thanks! |
|
| Back to top |
|
 |
Phil - Nottingham
Joined: 01 Jan 2008
Posts: 1252
Location: Nottingham
|
| Posted: Fri Dec 09, 2011 7:15 pm Post subject: |
|
|
Probably would be sufficiently brake fluid resistant but the rubber boots are there to keep out dust/water definitely not to keep the fluid in which just should not present or "loose" in the first place.
Its grease/oil/petrol resistance that is more important
_________________
Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2 |
|
| Back to top |
|
|
Nick.S.
Joined: 08 Nov 2011
Posts: 64
Location: Manitoba, Canada.
|
| Posted: Fri Dec 09, 2011 8:28 pm Post subject: |
|
|
thanks  , for the brake master cylinder there are two rubber seals inside, and i have a choice between silicon rubber and urethane rubber (guess i should have siad that before, sorry  )
which do you think is best for this application?
many thanks,
Nick. |
|
| Back to top |
|
|
Phil - Nottingham
Joined: 01 Jan 2008
Posts: 1252
Location: Nottingham
|
| Posted: Fri Dec 09, 2011 9:04 pm Post subject: |
|
|
I would not even contemplate using home made seals in brakes for this purpose - there must be some modern equivalent as standard sizs were used from the outset for propriety systems that all UK manufacturers fitted
_________________
Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2 |
|
| Back to top |
|
|
D4B
Joined: 28 Dec 2010
Posts: 2083
Location: Hampshire UK
|
| Posted: Fri Dec 09, 2011 9:34 pm Post subject: |
|
|
My Lockheed Catalogue 1959 - 1970 says both the A40 Mk1 and A40 Mk11 need Brake Master Cylinder Repair Kit KL71535
I am sure I have seen those kits new old stock at car shows...
If not found this in 5 mins searching google 4u
Good Luck
http://www.earlpart.co.uk/catalogue%20a30.pdf |
|
| Back to top |
|
|
Jim.Walker
Joined: 27 Dec 2008
Posts: 1229
Location: Chesterfield
|
| Posted: Fri Dec 09, 2011 10:26 pm Post subject: |
|
|
Casting your own brake seals! A terrifying prospect.
Please send me a private message if you intend coming anywhere near me and I will stay safely at home!
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then! |
|
| Back to top |
|
|
ukdave2002
Joined: 23 Nov 2007
Posts: 4104
Location: South Cheshire
|
|
| Back to top |
|
|
Nick.S.
Joined: 08 Nov 2011
Posts: 64
Location: Manitoba, Canada.
|
| Posted: Sat Dec 10, 2011 6:27 pm Post subject: |
|
|
ha, sorry, never thought about it like that! i suppose at very worst if the brake cylinder failed totaly, theres still the mechanical rear breaks 
of course, though out this rebuild im trying to be as safety oriented as possible. the reason behind thinking about making seals is they are a strange looking hollow section square form o-ring and i couldnt find any
D4B, earlparts looks fantastic! i will definatly contact them about parts.
we dont have to many auto jumbles here in manitoba, so i try to find a lot of parts on ebay.
agian, thank you,
Nick. |
|
| Back to top |
|
|
Jim.Walker
Joined: 27 Dec 2008
Posts: 1229
Location: Chesterfield
|
| Posted: Sat Dec 10, 2011 10:48 pm Post subject: |
|
|
| Nick.S. wrote: | ha, sorry, never thought about it like that! i suppose at very worst if the brake cylinder failed totaly, theres still the mechanical rear breaks
of course, though out this rebuild im trying to be as safety oriented as possible. the reason behind thinking about making seals is they are a strange looking hollow section square form o-ring and i couldnt find any
D4B, earlparts looks fantastic! i will definatly contact them about parts.
we dont have to many auto jumbles here in manitoba, so i try to find a lot of parts on ebay.
agian, thank you,
Nick. |
If you study the seals carefully you will find they taper very slightly from the front lip to the back edge, which forces them to expand slightly under pressure for a good seal. The lip on the front edge is also as sharp as a knife edge (or would be if it was steel). ANY imperfection in that edge will mar the sealing.
I doubt if any "home" casting, however good, could ever replicate the shape accurately enough.
Oh, and by the way. Have you ever tried stopping quickly on rear brakes alone? With probably only about 40% of the vehicle weight on the rear wheels, timing the stop would be better done with a calendar than a stop-watch!
JIm.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then! |
|
| Back to top |
|
|
Nick.S.
Joined: 08 Nov 2011
Posts: 64
Location: Manitoba, Canada.
|
| Posted: Sun Dec 11, 2011 8:52 pm Post subject: |
|
|
i will buy new seals for the brakes.
these seals are not normal cup seals, which need a perfectly sharp edge, these are flat, when you press the brake pedal there is a slight bit of pressure compressing them out a bit forming a perfect seal.
i will attempt some photos
 |
|
| Back to top |
|
|
Nick.S.
Joined: 08 Nov 2011
Posts: 64
Location: Manitoba, Canada.
|
| Posted: Sun Dec 11, 2011 8:58 pm Post subject: |
|
|
hey, that worked 
sorry about the jittery pictures. the cylinder are in nice shape, but the rubber has turned to goo.  |
|
| Back to top |
|
|
Jim.Walker
Joined: 27 Dec 2008
Posts: 1229
Location: Chesterfield
|
| Posted: Sun Dec 11, 2011 11:13 pm Post subject: |
|
|
You only show one seal on there! There should be 2 seals on this (Lockheed type) piston and cylinder.
The front seal needs to let fluid past on the reverse stroke (only) and the other seal prevents fluid escaping past the piston.
If the front seal is not functioning properly in BOTH directions there will be no emergency "pump up" at the pedal. If the rear seal is not extremely accurate in size and lip position it can either prevent fluid entering from the reservoir or do the opposite and cause the brakes to lock on.
Perhaps not such a simple problem as you first thought?
Jim.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then! |
|
| Back to top |
|
|
Nick.S.
Joined: 08 Nov 2011
Posts: 64
Location: Manitoba, Canada.
|
| Posted: Thu Dec 15, 2011 12:12 am Post subject: |
|
|
| ahh, yes, this is making sense. i knew there were two seals in there ( i bought a service manuel for it) but i cant get the end cover off, its to tightly torqued on. i will see what i can do to get that apart |
|
| Back to top |
|
|
michael1703
Joined: 22 Jul 2009
Posts: 349
Location: suffolk
|
| Posted: Thu Dec 15, 2011 8:43 am Post subject: |
|
|
what bore size is it?
A seal kit for a rover p4/p5/land rover series 1/series2 should fit that |
|
| Back to top |
|
|
|
FAQ
Search
Memberlist
Usergroups
Profile
Log in to check your private messages
Log in
