Brake Servo rubber hose - replacement

Objective

Objective

Member
I realise that this is a small detail, but in an attempt to avoid a difficult to replace part, can someone provide their experience on replacing the rubber vacuum hose. The section looping over the 1971 2000 TC engine from the carb is shot. Its been replaced before simply by cutting the hose around 6 inches from the servo and adding a simple, straight-through connector. Now the connector and the original 6" section also needs replacing.

So, to the question . . . the photo shows the jubilee clip removed, which should mean the hose should just pull off. It doesnt ! The fitting into the servo seems to be 2-part. If I apply more pressure, will the hose finally slip gently off, or will the plastic-looking connectors into the servo crack. Would you experienced people just pull off the hose, cut it off or reconnect another straight through connector, safe in the knowledge the original hose will (probably) last another 5 years, no problem.

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I did this job only this week, I ended up using Stanley knife to carefully cut most of the way through the rubber over the white plastic and then eased off with a screw driver. it is meant to be a push on pipe but with age it doesn't and you rick breaking the fitting on the servo. the new pipe will just push on though
 
Thank you Julian, just the response I was hoping for ! A breakage of that white plastic part means sourcing from the UK to Greece, so you have probably saved me weeks !
 
Presumably you know to use vacuum hose and not ordinary hose? Vacuum hose is braced against collapsing, whereas ordinary stuff isn't.
 
Got that, but thanks for the reminder. Two layer with a bracing web of fibreglass between. It'll be affected by the heat of the engine as it loops over the top, but should be good for 10 years service.
 
The white plastic fitting is a one way valve to maintain vacuum in the booster case. Correct that pressure hose should not be used with vacuum - they have a tendency to delaminate.
 
The white valve is just pushed into the rubber ring there, it will come out without too much effort by prying with a tool between the white flange and the rubber ring. Once you have it out, you can twirst the valve to loosen it in the rubber hose, then pull it out. The comment about needing reinforced vacuum hose is technically right, but the hose is small enough diameter than it’s not an issue. It’s material, not construction, that leads to the delamination Jp mentions. I’ve used fuel service hose without problems but had air service hose rot at the ends.

Yours
Vern
 
Ah, a one way valve - its obvious now you've said it JP, and thanks for the alternative extraction method Vern, very useful.
What sort of vacuum are we talking about here? A fraction of an atmosphere (~ 0.5 bar) or something closer or above 1 bar? Its certainly a tight seal on ours - but that may be age related :)
 
If there's a vacuum in the pipe, although not a true vacuum which depends on throttle position. Then it's going 1 bar max, subject to altitude. ;)
 
I've used Parker hydraulic hose which is used in my industry. 3/8" with a thin steel wall inside. It won't burst or collapse.
 
Thanks Col, so the seals would need to be faily tight, interesting. I nearly worked for Parker at the start of my career. Good quality, reliable and fairly innovative.
 
I hope all this work on the engine will be fixed before you take it for a test drive prior to the rally! Sounds like you have really improved the engine
 
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