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Knocking Under Firm Braking.

Samuel Leonard
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Samuel Leonard Rising Star

Samuel Leonard

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more of a knock when i release the brakes slightly under firm braking. say firm is 60% as i release to 40% as i get closer to lights i hear a few loud knocks sometimes. anyone know what this could be? i fear the worst as something to do with ATTESA or the front drive shaft... but i'm hoping it's something common and an easy fix. i am a first year mechanic and am stumped but i have access to hoists for my car on saturdays so please help!

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https://www.sau.com.au/forums/topic/350126-knocking-under-firm-braking/
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Moodles2 Grand Master

Moodles2

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If it's coming from the front, it could be anything but I'll make a list of possibilites: CV joint, warped discs (since the front does all the braking basically), worn out suspension bushing (any suspension part is a possibility), wheel bearing on its way out, front diff low on fluid, sticky/seized caliper piston, clutch (throwout bearing on its way out for example), there are probably others but that's all I can think of.

Front drive shaft (or ATTESSA for that matter) is unlikely since under deceleration ATTESSA would be driving the rear wheels

SargeRX8 Grand Master

SargeRX8

Posted
Posted

Check your castor bushes. Broken castor bushes will give a thud or knock during breaking. My R33 GTST is giving weird clunks only on the right side when braking. Changed my damaged swaybar link today(its literally stuck in the ball joint). Doubt its gonna fix it. Anything rubber could be cracked and something could be moving out of place.

Samuel Leonard Rising Star

Samuel Leonard

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thankyou all for you input! i'll have a decent look soon! maybe tomorrow! i hate looking under my car at the moment due to all the leaks. it's 21 years old so i'm not surprised but i'm working my way out of debt and i'll do all it takes when i've finished paying off my loan.

thanks again!

Samuel Leonard Rising Star

Samuel Leonard

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When you say knock, does it like like creaking metal? I get this and the body is good, in the middle of replacing bushings all round atm, hopefully I find what it is along the way.

YES! EXACTLY! please tell me when you find it! almost sounds like abs but it makes this sound when i flip my 2wd switch and abs is on that circuit so it can't be that.

Samuel Leonard Rising Star

Samuel Leonard

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hey guys i just posted something very simliar. do u guys only get this during breaking? cause i get this sensation hear/feel pass side hump on the floor during breaking and acceleration. and for me it happens while in gear or out of gear

no idea what hear/feel pass side hump means lol but come to think of it, mine makes this sound out of gear too so it can't be drive train. surely it's a common problem then if 3 people have it within a week of posting so someone will have a fix... anyone? can't see anything under the car...

  • 4 years later...
SandalsBoy Enthusiast

SandalsBoy

Posted
Posted

Hi Guys,

Sorry to resurrect this thread , but I have a similar problem to what you describe on my 89 R32 GTR.

It occurs just before stopping or whilst taking off from stationary, there is a clunk (also kinda sounds like creaking metal but in a very short 1/4 second time span) from the front of the car. The problem doesn't happen when taking off very gently or stopping very gently but anything at a normal driving pace and it will happen.

Did any of you find the solution to this problem?

One other thing ill add is that once or twice the same sound occurred when I started the car (was in neutral / with handbrake on), which seems totally inconsistent with the above mentioned problem...

I have my car into the mechanics as I write this so, hopefully they find the culprit but if you can let me know if you found the problem, Im sure it will save a lot of time!

Thanks.

SandalsBoy Enthusiast

SandalsBoy

Posted
Posted

Got the car back from the mechanic. Apparently its the gearbox... what do you guys reckon? Sound plausible?

This could explain the couple of times the sound was heard when starting the car(stationary)... But I would have thought if it was the gearbox that it would present the issue 100% of the time upon start up, rather than on take off or just prior to becoming stationary.

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