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-   -   How to guide to replace front Brake Pads and Rotors on a W123 (http://www.peachparts.com/shopforum/diesel-discussion/236897-how-guide-replace-front-brake-pads-rotors-w123.html)

curtludwig 11-06-2008 11:42 AM

Thanks for this, I'm about to do this same job tomorrow.

I'm needing this car back on the road *NOW* so I won't be cleaning/repacking the wheel bearings but I will at some point (next week probably) soon. I'd like to have seen a couple steps about pulling the inner bearing/seal and cleaning/repacking. I'm also concerned that if I hadn't already asked a bunch of people about how to set the bearing tension that your method would tend to influence me to set them too tight.

I'm an instructor and the big thing I've learned (sometimes the hard way) is that people will misconstrue EVERYTHING you say. Its so important to be precise..

Also saying "whatever" when somebody gives you constructive criticism is just rude. I applaud you for your effort but theres just a couple little things that could make this writeup awesome (the pics are great btw!).

79Mercy 11-06-2008 11:54 AM

Quote:

Originally Posted by curtludwig (Post 2013458)
I'm also concerned that if I hadn't already asked a bunch of people about how to set the bearing tension that your method would tend to influence me to set them too tight.

why? I said snug it down and then turn the nut to the left until you feel it break free, then snug down the nut.

As for the rear bearing seal just pry it out with a flat head, its going to break so just buy a new one.

Brian Carlton 11-06-2008 12:21 PM

Quote:

Originally Posted by 79Mercy (Post 2013479)

As for the rear bearing seal just pry it out with a flat head, its going to break so just buy a new one.

This is a recipe for disaster. The bearing sits right behind it and the temptation is to use the face of the bearing for leverage. You cannot "pry" the seal from the hub..........you must "pull" it.

rrgrassi 11-06-2008 12:39 PM

A seal puller also tends to use the bearing for leverage.

Brian Carlton 11-06-2008 01:02 PM

Quote:

Originally Posted by rrgrassi (Post 2013543)
A seal puller also tends to use the bearing for leverage.

I never used the actual tool, but the leverage on the bearing doesn't seem to be a very good design. I've damaged the face of a bearing using leverage and would never advise anyone to approach it that way.

Far better to hook the seal and provide a vertical impact force on the "hook". Do this several times around the seal and it moves forward and out without any bearing damage.

MBeige 11-25-2008 12:26 AM

Just bumping this thread, where do I get a dial indicator? Went to the local auto parts stores and they don't have it...tried Autozone, Pep Boys, Kragen, no go.

Brian Carlton 11-25-2008 01:14 AM

Quote:

Originally Posted by MBeige (Post 2030621)
Just bumping this thread, where do I get a dial indicator? Went to the local auto parts stores and they don't have it...tried Autozone, Pep Boys, Kragen, no go.

Try these guys.........good prices for less than "professional" tools:

www.use-enco.com

whunter 11-25-2008 02:28 AM

Answer
 
Quote:

Originally Posted by MBeige (Post 2030621)
Just bumping this thread, where do I get a dial indicator? Went to the local auto parts stores and they don't have it...tried Autozone, Pep Boys, Kragen, no go.

Here are two suppliers I use all the time. :D

https://www.harborfreight.com/search?q=dial%20indicator

https://www.harborfreight.com/clamping-dial-indicator-63656.html

http://www.wttool.com

http://www.pts-tools.com

MBeige 11-25-2008 02:54 AM

Thanks, I found one at Harbor Freight and there's a store on my way home from work. Since I'll be doing the brake job tomorrow I might as well just pass by there. Hope they're open after 5, just in case!

Edit: What's the best way to remove the inner bearing? Instead of repacking I just bought new ones for peace of mind. SKF a good brand?

vstech 11-25-2008 10:14 AM

Quote:

Originally Posted by 79Mercy (Post 2013479)
As for the rear bearing seal just pry it out with a flat head, its going to break so just buy a new one.

this should read the Inner bearing seal... anyway, here's what I have done for years professionally and at home. it always worked for me, and it DOES NOT DAMAGE THE SEAL OR THE BEARINGS... if done carefully.

after you have popped out the outer bearing and set it in the dust cap, put the lock nut back on loosely, now gently pull the hub over the nut and rest the inner bearing against the lock nut, now slide the hub on a bit then pop it out against the nut. this will force the inner bearing race against the surface of the grease seal and pop both out of the hub.
********************************************************
warning!!! if not done correctly, you can damage both the inner bearing and the race of the inner bearing. so fully inspect both after the bearings are out, and be prepared to drive out the race and replace the bearings, race and seal. !!!
*********************************************************

you should then clean thoroughly, the inner, outer bearings, and completely remove all traces of grease from the hub, and the spindle. unless you are absolutely sure you have exactly the same brand and weight of grease as what is already in there. most high pressure greases do not mix well...
then re pack the bearings with your preferred grease and pack a thick layer of grease inside the hub. DO NOT FILL THE HUB WITH GREASE!!! just a layer around the inside of the hub.

Brian Carlton 11-25-2008 10:24 AM

Quote:

Originally Posted by vstech (Post 2030815)
.
********************************************************
warning!!! if not done correctly, you can damage both the inner bearing and the race of the inner bearing. so fully inspect both after the bearings are out, and be prepared to drive out the race and replace the bearings, race and seal. !!!
*********************************************************

...........and, without great knowledge and care, it will not be done correctly............

This procedure is fraught with risk...........I wouldn't advise it for anyone but a professional.

rrgrassi 11-25-2008 11:25 AM

Quote:

Originally Posted by Brian Carlton (Post 2013576)
I never used the actual tool, but the leverage on the bearing doesn't seem to be a very good design. I've damaged the face of a bearing using leverage and would never advise anyone to approach it that way.

Far better to hook the seal and provide a vertical impact force on the "hook". Do this several times around the seal and it moves forward and out without any bearing damage.

That is a good way. I have used big channel locks also.

I have also used a small cold chisel to bend the seal inward, but parallel to the bearing so I could get a flat head and pry it up against the lip of the hub.

MBeige 11-25-2008 05:37 PM

Quote:

Originally Posted by rrgrassi (Post 2030882)
That is a good way. I have used big channel locks also.

I have also used a small cold chisel to bend the seal inward, but parallel to the bearing so I could get a flat head and pry it up against the lip of the hub.

Won't that damage the seal?

BENZSTER 11-25-2008 07:55 PM

Wouldn't the preferred method be to open the bleeder on the caliper before depressing the pistons for pad installation? I am of the opinion that the brake fluid that has been exposed to the most heat and has the most probability of containing contaminants such as water would be nearest to the caliper. I certainily wouldn't want any possibly contaminated fluid pushed back up into an ABS controller as installed on my W126. Another point is if the master cylinder reservoir has been topped off between pad changes, when you go to push in the caliper piston to install the pads without opening the bleeder the possibilty exists that you may get some brake fluid shooting back through the hole in the top of the reservoir cap. Just my 2 cents..:cool:

Brian Carlton 11-25-2008 09:45 PM

Quote:

Originally Posted by MBeige (Post 2031262)
Won't that damage the seal?

When he states "inward", he means toward the centerline of the hub..........not parallel to the axis of the hub. To force the seal inward is diffcult because the chisel needs to bite into the surface of the seal and puncture it. Then, the seal can be forced "inward"..........and not "downward".

If you can damage it and force it inward, you'll be able to get a prying instrument on the hub to lift it upward without prying on the bearing.


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