Brake booster problem

**rar110** · 8th September 2013, 08:35 PM

The brakes on the 110 have taken a sudden turn for the worse.

The very start of the pedal is normal but then can feel a lot more pedal pressure is required. I suspect the brake booster is not doing its job.

Ive checked the vacuum pump is working and there are no leaks in the line from the pump to the booster.

Is the booster the problem?

My 110 has the ADF modified PBR booster and master cylinder if that's relevant.

thanks

**Blknight.aus** · 8th September 2013, 08:39 PM

the air vent may be blocked, it means you get no assist because air cant back into the booster when the push rod hits the valve to open the back chamber to atmosphere.

**rar110** · 8th September 2013, 08:43 PM

thanks Dave.

Where's the vent, how do I check that?

**wrinklearthur** · 8th September 2013, 08:46 PM

I have tried this to see if the vacuum boost was working.

Engine off, pump the brake peddle until all the vacuum is finished, while holding the peddle down firm, start the engine and then the peddle should draw down further as the vacuum is returned.
.

**wrinklearthur** · 8th September 2013, 08:50 PM

Originally Posted by Blknight.aus

the air vent may be blocked, it means you get no assist because air cant back into the booster when the push rod hits the valve to open the back chamber to atmosphere.

Dave's on the money.

I think the felt filter is around the push rod on those boosters.

.
.

**Blknight.aus** · 9th September 2013, 04:28 AM

its around the push rod on all boosters.

it may also be the valve sticking I generally dont try to rebuild the valve just replace it as a whole assembly but it can be done

**wrinklearthur** · 9th September 2013, 05:05 AM

Ref; https://www.google.com/url'sa=i&rct=...78756344506259

Some early series Land Rover are modified to have these 'VH44' fitted.

**wrinklearthur** · 9th September 2013, 05:22 AM

This diagram shows an exploded schematic for a booster fitted to a Corvette, it's similar to a booster fitted into the Land Rover

.

**rar110** · 9th September 2013, 05:39 AM

Thanks.

So bonnet off and access filter through top of the pedal box?

**rar110** · 9th September 2013, 05:42 AM

Originally Posted by wrinklearthur

I have tried this to see if the vacuum boost was working.

Engine off, pump the brake peddle until all the vacuum is finished, while holding the peddle down firm, start the engine and then the peddle should draw down further as the vacuum is returned.
.

I tried this. The peddle didn't draw down further after starting the motor.

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