Sporadic Suspension/Brake Thump
#1
Member
Thread Starter
iTrader: (2)
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.
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.
#2
Supreme Member
iTrader: (1)
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.
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.
#3
Member
Thread Starter
iTrader: (2)
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.
The hose blockage theory is new to me.
Thanks. I appreciate your help.
#4
Member
Thread Starter
iTrader: (2)
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.
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.
Thread
Thread Starter
Forum
Replies
Last Post
breathment
Tech / General Engine
7
03-29-2002 07:07 PM