Brakes no Servo Assistance

Technical advice Q&A

Topic author
motion32
Posts: 2
Joined: Mon Jul 16, 2018 3:55 pm
Location: Somerset UK
Great Britain

#1 Brakes no Servo Assistance

Post by motion32 » Mon Jul 16, 2018 4:18 pm

Apologies as I am sure this has been covered before but can't I find the answer.

Jaguar E-Type S2 Brakes have No Power Assistance. Almost impossible to stop the car pedal very hard to push.

Symptoms:-
a. When the engine is started and with foot on brake pedal no noticeable depression of pedal
b. Tickover is fine no misfire.
c. Fast actuation of throttle (flooring it on or off load) causes spitting back/missfire :?: initialy on rising revs then continues to increase revs OK.
d. When engine is ticking over if I press the Brake Pedal the Engine revs pick up by around 200 to 300 revs.
e. Brakes all free car rolls and drives fine.
All advice very welcome.

Dave

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cactusman
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#2 Re: Brakes no Servo Assistance

Post by cactusman » Mon Jul 16, 2018 4:38 pm

Sounds as though either the servo has failed or there is a major air leak somewhere between the inlet manifold, the air reservoir tank and the servo meaning the servo has no vacuum assistance or possibly the non return air valve on the air reservoir tank is faulty.
Julian the E-type man
1962 FHC
1966 MGB....fab little car too

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Topic author
motion32
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Joined: Mon Jul 16, 2018 3:55 pm
Location: Somerset UK
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#3 Re: Brakes no Servo Assistance

Post by motion32 » Mon Jul 16, 2018 5:06 pm

Thanks for reply,
Yes I guess the same, but I hope to get a logical fault finding procedure to locate actual fault
Dave

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politeperson
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#4 Re: Brakes no Servo Assistance

Post by politeperson » Mon Jul 16, 2018 5:20 pm

Why dont you pull off the servo hose from the inlet manifold? Then plug the inlet manifold servo pipe and rev the engine.

If the spitting stops it would suggest an air-leak of the brake vacuum side of things.
Its true, but Enzo never said it
Too many E types
XK120 SUs

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mgcjag
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#5 Re: Brakes no Servo Assistance

Post by mgcjag » Mon Jul 16, 2018 6:06 pm

Hi Dave...have a look in the Jaguar service manual..there are very detailed diagrams of how the braking system works....Steve
Steve
69 S2 2+2 (just sold) ..Realm C type replica, 1960 xk150fhc

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