[ambyrr22]

Hello! I'm a total newbie to both the forum and the world of TDI. I have a new (to me) 2004 Jetta TDI GLS. I hope someone can give me an idea about what might be causing a thump that happens when I brake. And yes, it's a thump, not a squeal, squeak, grind or anything like that.

Whoever had the car before me put aftermarket rims on it and the right front caliper was hitting the spokes. It was hitting hard enough that there was visible wear on both the caliper and the spokes. I thought this was what was causing the thumping because it seemed to make sense. The thumping was faster when the car was going faster and slowed as I came to a stop. This seemed to correspond to the caliper hitting the spokes.

I ground down the caliper to the point that it is no longer hitting the spokes, and I still have the thump.

I did have a mechanic look at it before I realized that the caliper was hitting. He found that the brake pads on it were practically brand new and of really low quality. He also found that the inner brake pad was loose in the caliper. He was able to tighten it but there is still more play in that pad than in the outer pad. I'm skeptical that this play is what is causing the problem because the noise didn't change at all when he tightened it.

If anyone can give me a suggestion for what to try next, I would really appreciate it!

Thanks,

Erin

 

[chittychittybangbang]

It could be the brake pad as you mentioned. These are floating brake calipers which mean one side is fixed and the other side floats to clamp on it. I forget which side slides, but the pins the caliper floats on could be bent, seized, from the contact. Could also be front suspension bushings.

 

[ambyrr22]

I was wondering about that. The entire front end creaks like an old mattress, but it's worse on the right side. I tried lubricating all the bushings I could find with white lithium grease, but the squeak is still as bad as ever. I just really don't want to have to replace my struts I've only had the car a week! But do you think that could be the problem? How do I properly diagnose it so that I'm not wasting money on struts if that's not the issue?

 

[ambyrr22]

Follow up question....if it was the front suspension, would it ONLY happen when I'm braking? The thump never happens any other time, but the creaky squeaky sound is pretty constant.

 

[Seatman]

Sounds like a possible broken or damaged reluctor ring, try removing the fuse for the abs, if the thump goes then that's what it'll be, seen it a few times and it doesn't seem to trigger the abs light.

 

[slickfast]

I was wondering about that. The entire front end creaks like an old mattress, but it's worse on the right side. I tried lubricating all the bushings I could find with white lithium grease, but the squeak is still as bad as ever. I just really don't want to have to replace my struts I've only had the car a week! But do you think that could be the problem? How do I properly diagnose it so that I'm not wasting money on struts if that's not the issue?

If I'm guessing right, the previous owner probably thought he was being slick by installing polyurethane bushings to give him more race-car like handling... because race car (it's an internet meme if you're not familiar ). Seriously though, if that's the case, he probably didn't lubricate them right. My recommendation is that if it is a poly bushing, take them out and grease them with MARINE grease. That's right, for boats. That stuff doesn't wear off and I've heard great stories of people using that and not hearing a peep from their poly bushings.

If that doesn't fix it, you might want to check whether the springs are properly seated in the struts. Those stupid aftermarket wheels might have knocked them out and it could be rubbing against something.

Follow up question....if it was the front suspension, would it ONLY happen when I'm braking? The thump never happens any other time, but the creaky squeaky sound is pretty constant.

Honestly I don't think it's the front suspension (unless your front wheel bearing are toast, which is not what's happening here from the sounds of it).

Think about it though: the thump happened because the rim was hitting the caliper. That means the caliper probably moved (stock brake caliper brackets are pretty weak, to be honest), which means the pads hit the rotor at that exact spot. Also remember that the brake rotor is fixed in relation to the wheel, and then think about the following. If the caliper got bumped, the rotor probably got hit by the pads repeatedly for that specific location on the rotor which corresponds to the part on the wheel that hit the caliper. So, the rotor probably wore away at that specific spot on the rotor. Make sense?

Basically if that's the case, replace the rotor and you should be good to go. Get some better pads while you're at it... they could save your life.

 

[wvfreeheel]

calipr hitting rim

I have the same problem and it is rim related. Rims that came with the car do not rub, but rims purchased as salvage do.

 

[Seatman]

I have the same problem and it is rim related. Rims that came with the car do not rub, but rims purchased as salvage do.

Try some spacers, I use 5mm ones to counteract the wrong offset on my wheels.