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Brakes dragging..
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2353
Location: MI

PostPosted: Sun Jun 20, 2021 7:23 am    Post subject: Brakes dragging.. Reply with quote

Brakes on the 941 are dragging and it might help me to bounce this diagnostic off some others here..

First it was the front right that I was really concerned about.. (bit of steering wheel shake 65-75 mph, could be brakes, could be the ruined front tires, new yoko a052 tires in hand-waiting for tire shops to open)

I took both of the front brakes all apart, exercised the pistons in and out a couple times, cleaned the sliders and put a dab of grease on the sliders..

Nope, still drag..

Noticed it was the front right and left rear hot this time.. Maybe in the master?

Adjusted the brake pedal lower, figured it might not be returning properly, it’s now far too low..

Drove 15 miles..
Nope still drag..

Now it’s both on the right side that are hot..
Actually, they are all a bit hotter than I’d think..

I pumped both front pistons out quite a ways and pushed them back in, so I know atleast with a C-clamp fluid will return to the Rez..

Pretty sure it’s the right rear that also squeaks a bit at very low speed, brakes not applied..

What to try next?
Swap the master from my other car and see if that solves it?

These brakes, pads and rotors seem like brand new.. Like brand new..
Could this just be a symptom of them not bedded in yet?

Ideas?
What to try?

Thanks..

How can I tell easily if it has a 4 lug master on it?

This car need to be ready to go on a thousand+ mile adventure in a few days..
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924RACR  



Joined: 29 Jul 2001
Posts: 8451
Location: Royal Oak, MI, USA

PostPosted: Mon Jun 21, 2021 9:57 pm    Post subject: Reply with quote

Hoses? I've seen or heard of them being able to retain pressure at the caliper, even though they bleed OK.
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Cedric  



Joined: 27 Aug 2004
Posts: 2173
Location: Sweden

PostPosted: Mon Jun 21, 2021 11:10 pm    Post subject: Reply with quote

Hoses and new seals in the calipers should probably be a good idea.
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Paul  



Joined: 02 Nov 2002
Posts: 9485
Location: Southeast Wisconsin

PostPosted: Tue Jun 22, 2021 4:29 am    Post subject: Reply with quote

Brake hoses have a 10 year life, check for dates on the hoses.
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2353
Location: MI

PostPosted: Tue Jun 22, 2021 6:13 am    Post subject: Reply with quote

New front tires didn’t fix it..
Steering feels super sharper now though and doesn’t want to push the front anymore with the new wider and much more stickie tires (205 to 225)..

Brakes are still **** though..


Bled the brakes yesterday at the calipers.. Went normal.. No change..

I agree the lines should be replaced.. they are old looking and feel a little spongey, but I don’t have time for that right now (shipping), and am still leaning towards the master..

Specifically the 2nd circuit on the front of the master..
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2353
Location: MI

PostPosted: Tue Jun 22, 2021 9:21 am    Post subject: Reply with quote

This is all about steering wheel shake..
It’s not like the brakes are dragging so bad they are getting extremely hot..

The culprit might not even be the brakes..


Just found the front right control arm bolt that goes through the crossmember about to fall out!!
Nut was barely on, tightened the crap out of it..

Test drive..
No change to shake, but now the steering wheel points left a bit

Gave the right side outer tie rod 3 turns of tow IN..
Will continue test driving tomorrow, trying everything..

Right rear brake makes a little noise at slow speed, but the rears turn easily..
All wheels turn quite easily really.. Might not be the brakes at all..

Frustrated..


At speed, about 60MPH is the worst of the shake, and I hate it very much..
Pushing the brakes during the shake does not change the shake at all.. Don’t feel it in the brake pedal..
The only time I feel anything in the brakes is at VERY low speed, like almost to a stop, where I can feel it grab and free up ever so slightly with wheel rotation..

I really hope these front rotors are OK because they are absolutely brand new looking.. Can still see the cross hatching machining marks on them brand new..

Grrr...

Maybe I’ll take a video tomorrow..
Hopefully the 3 turns of tow in on the right front will have fixed it though..
Yeah right..
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safe  



Joined: 18 Mar 2017
Posts: 304
Location: Sweden

PostPosted: Tue Jun 22, 2021 7:31 pm    Post subject: Reply with quote

Wheel bearings to much play?
Tie rods worn?
Ball joints worn?
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2353
Location: MI

PostPosted: Tue Jun 22, 2021 11:33 pm    Post subject: Reply with quote

The only thing I found was that loose control arm bolt..
I am very sure of all of the suspension components other than the outer control arm ball joints as they are hard to check, but I can’t find any play in them..
All tight.. wheel bearings seem adjusted very well..

3 turns of tow in didn’t help at all..
5 mile test drive and all 4 brakes are quite hot, but I did use them a bit so not sure..

Next I’m going to go swap the master..
If that doesn’t work then maybe I’ll start swapping everything else..
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safe  



Joined: 18 Mar 2017
Posts: 304
Location: Sweden

PostPosted: Tue Jun 22, 2021 11:54 pm    Post subject: Reply with quote

Does it shake in the front wheels or the rear?
Does it change if you swap the wheels front to rear?
If you apply a light braking during the shake, does it increase or decrease?
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2353
Location: MI

PostPosted: Wed Jun 23, 2021 12:00 am    Post subject: Reply with quote

safe wrote:
Does it shake in the front wheels or the rear?
Does it change if you swap the wheels front to rear?
If you apply a light braking during the shake, does it increase or decrease?


Shakes all over.. Front and back.. (I think, so hard to tell)
Definately shakes enough I can see the rear hatch shaking..
Definately shakes the steering wheel..
Sometimes worse than other times, sometimes some rotors hotter than others, sometimes all hot..

Can be dead cold and starts shaking as soon as it gets up to speed.. Doesn’t take time..

Can’t swap the wheels front and back.. Have another set of wheels (late offset though so would look stupid) to swap and see if that changes anything just for a test..

These front wheels just got brand new tires and balanced yesterday..
If one was bent wouldn’t that have shown up when balancing them?

Braking during the shake doesn’t really change anything.. Doesn’t increase or decrease.. Don’t feel it in the brake pedal..
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safe  



Joined: 18 Mar 2017
Posts: 304
Location: Sweden

PostPosted: Wed Jun 23, 2021 12:17 am    Post subject: Reply with quote

Fasteddie313 wrote:
safe wrote:
Does it shake in the front wheels or the rear?
Does it change if you swap the wheels front to rear?
If you apply a light braking during the shake, does it increase or decrease?


Shakes all over.. Front and back.. (I think, so hard to tell)
Definately shakes enough I can see the rear hatch shaking..
Definately shakes the steering wheel..
Sometimes worse than other times, sometimes some rotors hotter than others, sometimes all hot..

Can’t swap the wheels front and back.. Have another set of wheels (late offset though so would look stupid) to swap and see if that changes anything just for a test..

These front wheels just got brand new tires and balanced yesterday..

Braking during the shake doesn’t really change anything.. Doesn’t increase or decrease.. Don’t feel it in the brake pedal..


If it shakes in the steering wheel its from the front, otherwise probably the rear. Brake issues should be noticeable in the pedal and change with adding brake pressure .

Sounds like something other than wheel/suspension/brakes...
Not sure how something really bad in the torsion tube would manifest itself. Are your drive shafts ok?
Any difference in acceleration, steady state, deceleration (engine braking)?
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Cedric  



Joined: 27 Aug 2004
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Location: Sweden

PostPosted: Wed Jun 23, 2021 2:08 am    Post subject: Reply with quote

I recently changed rear stub axle since it wasnt straight anymore and caused a wobble. It could easily be seen if i jacked the car up and ran it in gear. Or measured at the rim. I have no idea how it happened though..
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2353
Location: MI

PostPosted: Wed Jun 23, 2021 2:24 am    Post subject: Reply with quote

Has one bad boot on drivers side inner CV joint..
Doesn’t feel very sloppy or anything though..


Swapped the master.. NO CHANGE..
All 4 brakes too hot to touch in 5 miles including 2 stops, stops from like 30mph.. (engine braking first)

I’m about to remove the vacuum from the booster and cap the line.. See if that does anything..

When I removed the master, when I cracked loose the 2 bolts that hold it to the master, it hissed..
It either had vacuum or pressure between the master, engine off, full stop..
Not sure if that is good or bad..
Booster does work (power brakes)..
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Fasteddie313  



Joined: 29 Sep 2013
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Location: MI

PostPosted: Wed Jun 23, 2021 2:47 am    Post subject: Reply with quote

Depowered brakes..
Still shakes the same..
Brakes maybe not quite as hot but still to hot to hold my finger on for more than a second or 2..
Will leave depowered for now..

Used like zero brakes..

BTW I did take my 3 turns back out of the tow after DT first test drive today..

About to measure the runout of the front wheels and front brake rotors..
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2353
Location: MI

PostPosted: Wed Jun 23, 2021 4:12 am    Post subject: Reply with quote

Wheel runout is like 60 thousandths.. Axial and lateral, inside and outside.. Pretty good..
I imagine anything within the limits of my dial indicators range is acceptable..

Swapped 928 S4 8” gullydeckles with 245/50s on them..

Still shakes in exactly the same speeds but feels dampened, I imagine by the bigger/heavier wheels tires..

Same same no change..
Brakes too hot to hold from 2 stops in 5 miles..

Now what?

Swap the entire front brakes including lines off of my brown car?
Lol

Might as well blow out the lines while I’m at it..

Maybe.. we’ll see..
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