Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!

Sporadic Suspension/Brake Thump

Thread Tools
 
Search this Thread
 
Old 10-25-2012, 08:18 PM
  #1  
Member
Thread Starter
iTrader: (2)
 
ĦMR.AWESOME!'s Avatar
 
Join Date: Apr 2007
Location: Ashburn, VA
Posts: 184
Likes: 0
Received 1 Like on 1 Post
Car: '92 RS
Engine: 305 TBI
Sporadic Suspension/Brake Thump

Hey. I have the stock standard brakes. I replaced both front rotor hub assemblies two weeks ago and replaced the pads. I also replaced the inner hub bearings. This was the first time I have done this, so it's entirely possible I messed something up.

My problem is twofold. Firstly, while driving there is a knock/thump that I feel coming through my feet. I feel it the most when my foot is resting on the clutch pedal but also feel it through the floorboard. The thump is sporadic and is noticeable at all speeds above ~20MPH. By sporadic I mean it does not repeat at any consistent interval. This thump/knock goes away while braking.

The second problem is that the left-front wheel does not spin freely. When the car is jacked up, the right-front will spin for a good little while if I give it a twirl. The left-front spins about 1.5-2 rotations before it stops. When I take the wheel off and turn the hub, the caliper kind of sticks for a bit and the end smacks in to the part that the caliper bolts on to (spindle?) before it turns with a lot of friction. When I remove the caliper, the hub spins just fine. So I'm thinking that the caliper piston is not retracting enough when brake pressure is released. The hard spinning left-front symptom was there previous to the work I did, btw, but the noise was not.

The car drives fine. When braking, it does NOT pull to one side or the other. I did bed-in the pads and rotors, btw.

So what's causing the noise? Is it the caliper moving around? Is it the new bearings?

Thanks.
Old 10-25-2012, 08:38 PM
  #2  
Supreme Member
TGO - 10 Year Member
iTrader: (1)
 
sofakingdom's Avatar
 
Join Date: Sep 2005
Posts: 26,511
Received 1,862 Likes on 1,418 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Sporadic Suspension/Brake Thump

Calipers are like $12 apiece and the hardware that holds em on is like $3.

Some things in life aren't worth messing with if a coupla coins will fix it for you.

Just change it all out and move on.

YOu may also find that the rubber hoses have failed. They way those go bad is, the little fittings at the ends with little tiny pinholes in them, get rusty, and the holes get blocked. WHen that happens, the force (HUGE) that your foot puts on the system, can force fluid INTO the calipers; but the force that the caliper can put on the fluid to push it back (tiny) isn't enough to make the piston return. So while you're changing out the calipers, might want to renew both of those as well. They're SUPER CHEEEEEEEEEEEP too.

You'll probably want to buy a set of pads; unfortunately, they cost more than the whole rest of that all put together. Usually up around $30 - 40 or so for the decent ones. Rip-off. Oughta be a law.

Come back and let us know how it worked out.
Old 10-25-2012, 08:58 PM
  #3  
Member
Thread Starter
iTrader: (2)
 
ĦMR.AWESOME!'s Avatar
 
Join Date: Apr 2007
Location: Ashburn, VA
Posts: 184
Likes: 0
Received 1 Like on 1 Post
Car: '92 RS
Engine: 305 TBI
Re: Sporadic Suspension/Brake Thump

Cool. I was planning on doing the caliper tomorrow/this weekend actually.

The hose blockage theory is new to me.

Thanks. I appreciate your help.
Old 10-27-2012, 02:32 PM
  #4  
Member
Thread Starter
iTrader: (2)
 
ĦMR.AWESOME!'s Avatar
 
Join Date: Apr 2007
Location: Ashburn, VA
Posts: 184
Likes: 0
Received 1 Like on 1 Post
Car: '92 RS
Engine: 305 TBI
Re: Sporadic Suspension/Brake Thump

Good news!

I replaced the caliper and hose and the bump/thump/clunk is gone. The wheel spins freely and all is good.

Thanks for the help sofa.
Old 10-27-2012, 04:05 PM
  #5  
Supreme Member
TGO - 10 Year Member
iTrader: (1)
 
sofakingdom's Avatar
 
Join Date: Sep 2005
Posts: 26,511
Received 1,862 Likes on 1,418 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Sporadic Suspension/Brake Thump



Cheeep and eeeezy
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
eustodp
Electronics
8
09-20-2015 05:09 PM
db057
Tech / General Engine
4
08-22-2015 08:17 PM
breathment
Suspension and Chassis
4
10-27-2003 09:52 AM
breathment
Tech / General Engine
7
03-29-2002 07:07 PM
Eightyninef
Suspension and Chassis
5
10-04-2001 09:28 AM



Quick Reply: Sporadic Suspension/Brake Thump



All times are GMT -5. The time now is 09:16 AM.