Brake Booster Vacuum Valve Replacement (TJ / XJ)

Jayramble

Jayramble

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Have both 99 models of TJ & XJ, both 4.0 litre - need new brake booster vacuum check valves - the part numbers appear different on the parts manuals I can find, yet they appear identical when compared side by side and are fit interchangeable - but are the internals the same specifications, gaps, pressure allowed/created, etc.

In reality can I / should I use one in the other, etc.?

Any guidance from a real expert or experience with braking systems appreciated.

John
 
I compared the plastic 90* fitting of a '98 against a '99 and a 01; they appear the same.
Are you sure you didn't look up the part numbers for the proportioning valves on these vehicles ?
 
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Hi Charles, I used the part numbers from the charts parts manuals online as yes they all appear the same. Then I completed online searches for these parts and they did not appear to have listings of what other Jeeps they fit (i.e. the TJ part number did not list compatibility with XJ and vice versa). But they all look the same and the TJ brake booster check valve works okay for now in my XJ as my XJ check valve had a split in it.
1645595983951.png


TJ Part No 4584098 and XJ Part No J4487455
1645596161983.png
 
@mrblaine thanks - I don't know enough as to the design or technical specifications as to why one may be different to another except by guessing the inner chamber may regulate the pressure to different specifications - the inwards and outwards outlets on the check valve appear identical as does the external appearance. FYI, the TJ brake booster check vale seems to work well in my XJ so unless someone tells me otherwise they appear interchangeable - fingers crossed.
 
Jayramble said:
@mrblaine thanks - I don't know enough as to the design or technical specifications as to why one may be different to another except by guessing the inner chamber may regulate the pressure to different specifications - the inwards and outwards outlets on the check valve appear identical as does the external appearance. FYI, the TJ brake booster check vale seems to work well in my XJ so unless someone tells me otherwise they appear interchangeable - fingers crossed.
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I'm practically certain there is no regulation involved. It is just a check valve to hold vacuum in the booster to give you a few pedal applications with assist if the engine dies. If it weren't there, then as soon as the engine quits, you would lose all assist.
 
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