I have changed my brake booster today after suspecting it was leaking a little.

My brakes have been overhauled recently, but they still seemed pretty crap TBH and I have read plenty on here about them been considered crap so thought that was that.

I was lucky to get a spare brake booster with my manual conversion kit, so decided to whack it on (PITA, but DIYable!).

Well there is definately a difference and now it is possible to lock the front wheels on a dry road and activate the ABS!!! They are a lot better and they are STOCK (fast road pads only).

I would now describe them as good brakes as long as you don't cook them.

Best of all, its really easy to check the booster....

For those that don't know, pull the vacuum hose off the booster, blow hard on the connection. You should go RED faced and not be able to blow anymore.

I was able to blow, blow and blow into mine indicating the diaphragm has a very small hole in it and the air is passing through into the cabin. I checked my replacement was OK before fitting it.

So, like I said, my brakes were just OK before, but crap TBH, not a pray of locking the fronts, really struggled in the wet! As soon as this was changed, went for a blast, ABS operating, some tyre squeal - bone dry roads! Much better.

I always thought Nissan would not have produce a 300bhp car with such poor brakes and I wonder how many other duff boosters are currently in service.

Still considering larger discs, but I am thinking it is not necessary any more!)

 

Food for thought!:)

Nice one Bud, I`m gonna check tommorrow, as my brakes are CRAP!!!

Excellent tip mate! I've thought mine are pretty pants so will defo check this as well!! Thanks ;-)

 

Any pics though for a total noob?

No pics I'm afraid.

 

Open the bonnet, looking at the engine top left side, brake booster is a black round tank type device that the master cylinder bolts to. The booster usually has ABS in a yellow label on it at the top.

There will be a thick vacuum hose connected to it on the front flat face. Pull it off there and blow into the booster. You should go red faced and not be able to continuously blow more in. If you can, the diaphragm has failed and you may occasionally hear a squeaking noise from the brake pedal under hard braking.

HTHs

Great help thanks! I think I know where you mean...also the engine diagram on the forum should fill in any blank spaces in my head!

 

Thanks bud! Will defo check this tomorrow then!

Mine are crap too, thought it was cos it's been stood for ages, but will check it out! You can probably buy a new diaphragm instead of a complete unit too.......

great advice mine was gone too thanks bud, i like you had asumed they were just crap and was on my way to a big brake conversion but we'll see how this goes

while on the subject of brakes, when i press the pedal i hear a squeeking noise is this supposed to happen, i have no issues with my breaks that im aware of just a noise that i have always had since owning the car..?

i press the pedal i hear a squeeking noise is this supposed to happen

 

They all do that.

 

Also a leaking servo will also make the tickover bad as the fuel air mix will be too weak.

i press the pedal i hear a squeeking noise is this supposed to happen

 

They all do that.

 

Also a leaking servo will also make the tickover bad as the fuel air mix will be too weak.

 

No they do not all squeak.....if you get a squeak type noise under hard braking from the behind the dash it maybe the booster that has failed.

I have had a leak on my booster for 2years, yes it did make the idle a little rough, but since I have changed it the squeak has gone.

 

Jonny - test your booster as described above.... Obviously its not forced to be that, a squeak can come from the spring/s and linkages.

nice tip I'm going to check mine!!

Great top tip matey, this must be added to the buying guide or made into some sort of sticky, for peeps to read and relate to abou the crappy brakes nissan put on a 300zx, and maybe just as you say.... brake boost diaphram leak. Am sure one of the tech/mods will get this in place.

 

well done buddy!!

 

Al.

Cheers!:)

 

Changing it sure made a difference, hard braking much improved, but they still fade easily.

Still room for improvement with bigger discs etc, but must make sure the basic components are all in good working order first.

Can't believe I lived with it since I bought the car, the odd squeak it made was just as annoying as the poor braking....

My idle is smoother as well, but it was only a small leak.

 

On a side note, changing the booster is possible without completely removing the master cylinder, I unbolted the master from the booster and eased it out of the way, unbolting the unit from under the dash is back breaking, but do-able without removing any trim....

 

Like I said, a good improvement, well worth checking, but still not to Ferrari standards.

i would love to know where you guys are gettin your cars mot'd brake servo's should be checked as part of the test. easy way to check themwithout going under bonnet is this, ignition off press brake pedal hard 4 or 5 times this depletes vacume in servo, now press hard on brake and at the same time start engine , you should feel brake pedal sink an inch or so this indicates servo is ok, if pedal doesnt sink then theres something wrong.