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  #1  
Old 06-25-2006, 01:15 PM
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Subjective Brake Feel

89 300E
This is a recent purchase and I would say the brakes feels a little less firm from other German cars I owned. Now sure if it is the automatic vs. manual transmission feel. It seems the pedal FEEL is a little softer and less firm than what I am accustom to. I have bled the system and the master cyl. LOOKS fresh. Not sure if that has ever been changed. Just trying to find others opinions before I start changing parts.

Thanks.

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  #2  
Old 06-26-2006, 07:29 PM
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What brand of pads are on the car? I'll only use Textar pads from the dealer, as they give me the proper "feel".

I had one 94 E420 that I could only get to stop squealing with new rotors and pads from the DEALER. The supposedly equivalent OEM brake parts I was getting from another online dealer (not PartsLane) (Brembo rotors and Pagid pads) just were not up to the job. They squealed and warped within 2k miles.

Of course, the lug bolts were properly torqued and MB anti-squeal paste was used.

Only original rotors and pads from my local dealer performed satisfactorily, quiet, good feel, AND LOTS OF DUST I can live with brake dust.
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  #3  
Old 06-26-2006, 09:57 PM
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I have a dramatically different feel between the SD and the '86 SDL.

The SD feels classically German with very little modulation and a firm pedal within about 1/2" of travel. It won't go further without quite a bit of force and the vehicle will be hauling itself to a stop very quickly.

The SDL is the exact opposite. The brakes come on very gradually.....starting at about 1/4" and continuing to about 1.25" where they firm up in similar manner as the SD. But, for that extended range, they have a very gradual application and each time I get into the SDL, it's a bit disconcerting.

The SDL uses Textar pads all round and it's been bled more times than I care to count so I'm fairly sure it's not air in the system.......but........can't be 100% sure given the differences between the vehicles.
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Old 06-26-2006, 11:35 PM
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My brakes feels like your SDL. It feels very indirect compared to any German cars I have driven or owned. I am in the process of bleeding the system again, but I don't have high hopes. I was thinking of changing the master cyl. but it looks so new. Don't have the history if or when it was replaced though, and thought I would ask for how others evaluated their braking systems. My BMW is so solid and so easy to modulate. Pads, I am running Repco or whatever they call themselves now. I may try some Porterfield next.

Appreciate the thoughts and insight.

Quote:
Originally Posted by Brian Carlton
I have a dramatically different feel between the SD and the '86 SDL.

The SD feels classically German with very little modulation and a firm pedal within about 1/2" of travel. It won't go further without quite a bit of force and the vehicle will be hauling itself to a stop very quickly.

The SDL is the exact opposite. The brakes come on very gradually.....starting at about 1/4" and continuing to about 1.25" where they firm up in similar manner as the SD. But, for that extended range, they have a very gradual application and each time I get into the SDL, it's a bit disconcerting.

The SDL uses Textar pads all round and it's been bled more times than I care to count so I'm fairly sure it's not air in the system.......but........can't be 100% sure given the differences between the vehicles.
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  #5  
Old 06-26-2006, 11:41 PM
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Quote:
Originally Posted by krjt
My brakes feels like your SDL. It feels very indirect compared to any German cars I have driven or owned. I am in the process of bleeding the system again, but I don't have high hopes. I was thinking of changing the master cyl. but it looks so new. Don't have the history if or when it was replaced though, and thought I would ask for how others evaluated their braking systems. My BMW is so solid and so easy to modulate. Pads, I am running Repco or whatever they call themselves now. I may try some Porterfield next.

Appreciate the thoughts and insight.
I failed to mention that I recently changed the m/c on the SDL because it would have a touch of "pedal fade" on heavy applications. Not enough to be a problem, but, presumably, the m/c had an internal leak past one of the pistons.

The change of m/c cured the slight pedal fade. The soft modulation of the pedal is unchanged......and I must have put one quart of fluid through three of the wheels.
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  #6  
Old 06-27-2006, 12:00 AM
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Pedal feel can be effected by wheel bearing load being too loose..........
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  #7  
Old 06-27-2006, 12:17 AM
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Quote:
Originally Posted by Arthur Dalton
Pedal feel can be effected by wheel bearing load being too loose..........
.........too loose to what amount?? I can't see a clearance of .005" making any difference to the brakes.

I'll double check the SDL for axial play in the bearings, but, I'd be shocked if it was more than .005" (against a .0005" specification).
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  #8  
Old 06-27-2006, 11:56 AM
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Quote:
Originally Posted by Brian Carlton
.........too loose to what amount?? I can't see a clearance of .005" making any difference to the brakes.

I'll double check the SDL for axial play in the bearings, but, I'd be shocked if it was more than .005" (against a .0005" specification).

Is this loose wheel bearing thinking similar to the feel from a brake disc with too much run out?

I was questioning the hard/firm pedal feel that I normally get from german vehicles.
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  #9  
Old 06-27-2006, 12:06 PM
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Location: Florida / N.H.
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Loose bearings will increase the piston residual return measure and the pedal travel upon reapplication of the brakes.
It also causes cocking of the rotor to spindle.
Just something to check.

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