Mystery Thud

[Nismo_Freak]

Me and a Mazda Master Tech took a look at my 240 up on the lift to sort out a thud I get. Here is what I can tell you about it:

When it Happens:- It happens when the brake pedal is depressed in moderate to heavy braking, very rarely on light pedal pressure. - It happens when traveling over speed bumps at low speeds, not all the time though.

What it is:- It's an audible thud or popping noise that sounds similar to something being loose or having excessive play. - Vibration can be felt in the car and through the steering wheel when it happens.- Sometimes happens when reversing & turning; do not recall being on brakes at time of noise. - It is coming from the front of the vehicle

What I've Checked:- We checked the tie rod ball joints for play and they seem to be in spec. - I checked the steering for any binding; found none- Checked upper suspension and strut bolts for loose fitting; found none- Tension rod bushings are new

What I Suspect:- Lower control arm bushings- Possible lower arm ball joint going bad- Caliper piston sticking (?)

Any ideas?

[NISTECH]

well i was gonna guess torsion rod bushings in the front were bad until i got to the bottom and caught the tension rod bushings replaced. have some one watch your front tires while you hammer the brakes while creaping forward. then do the same with the other. what i have seen is those bushings go out and the front tires shift pretty hard to the rear. and have that "thud" as you described. thanks for you help out of the service manual on that code 95 cps for matt.

[Nismo_Freak]

No problem, I'm was a tech till today for Mazda. I'm looking to persue my own venture now.

The bushings are polyurethane so they can't really die like the old fluid filled rubber ones. However the rest of the bushings are rubber. I got a friend that has a full bushing kit for my car that he picked up from someone dropping their project. I'll see if I can eliminate it with those.

I don't feel like aligning my car again though

[NISTECH]

did you check your sway bar links and mounts?

[Nismo_Freak]

No, however I wouldn't think that the sway bar would be under load at 5 mph with gentle braking in a straight line.

[NISTECH]

no but you said it was moderate to heavy braking. thats what i went back too. what i was telling you to do earlier was if the tension rod bushings were bad.

[Nismo_Freak]

Ahhh... sorry I'm being a bit hypocritical I suppose. I'll have a look at them sometime.