# S Type brake booster

**URL:** <https://community.cartalk.com/t/s-type-brake-booster/79218>\
**Category:** Maintenance/Repairs\
**Tags:** jaguar, s-type\
**Created:** [May 9, 2013, 6:53pm UTC](https://community.cartalk.com/t/s-type-brake-booster/79218 "2013-05-09T18:53:51Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![wilelec](https://avatars.discourse-cdn.com/v4/letter/w/d9b06d/32.png) [@wilelec](https://community.cartalk.com/u/wilelec)\
**Post date:** [May 9, 2013, 6:53pm UTC](https://community.cartalk.com/t/s-type-brake-booster/79218/1 "2013-05-09T18:53:51Z")

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Brake booster problem on 2005 S/type 2.7 diesel auto  
Initial braking ok, but holding down pedal lightly makes next braking needing more & more brake pressure to get any braking

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<div class="post-metadata">

**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\
**Post date:** [May 9, 2013, 7:51pm UTC](https://community.cartalk.com/t/s-type-brake-booster/79218/2 "2013-05-09T19:51:35Z")

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@wilelec

Soft pedal = air in brake system, failing master cylinder, failing hydraulic control unit, leak, etc.

Rock hard pedal = faulty brake booster, vacuum problem

If you have the soft pedal, I suggest bleeding the brakes with a diaphragm brake bleeder and the appopriate adapter. Completely replace all of the fluid this way. Then retest. If it’s not better, you may have a failing component