Brake fluid change believer

[jeffc280sl]

As I replace the axle on my 280SL I've been going through all of the rear end components and making repairs as needed.  I've posted some pictures of calipers which came with the two donor axles I bought and assumed their poor condition was due to sitting around ourside and not being in service. That assumption was not correct.  Here are some pice of various rear brake compnents on my car which I thought were in okay shape.  I was very wrong.  The first picture shows a stuck caliper.  You can see from comparing the pad thicknesses from each side that one side was stuck.

Download Attachment: stuck caliper.jpg
29.5 KB


The next picture shows a good view of the uneven pad wear.



Download Attachment: uneven wear.jpg
31.36 KB

The rest of the pitures are of dirty pistons and rust clogged seals.



Download Attachment: piston seals.jpg
40.71 KB



Download Attachment: pistons.jpg
19.18 KB

What I thought was a pretty solid rear braking system turned out not to be.  I was very surprised and suggest we all take a look at our brakes in detail and change the brake fluid regularly.

Happy Thanksgiving,

Jeff C.
1970 280SL 4-speed

[mdsalemi]

Jeff,

Sorry you had this trouble.  You are "preaching to the choir" here.  I'm a firm believer in annual fluid changes, and have done so on all the cars I owned.

My mechanics at Motorwerks have a modern system that allows them to pretty much completely evacuate the braking system of old fluid as well as bleed it--connects to all 4 brakes simultaneously.  This does a better job for 1 hour of labor then you can do in your own garage or driveway--though I think there are some more automated systems for the DIYer.

Have a happy Thanksgiving, too!

Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored

[norton]

This what I've been using to bleed brakes with  http://www.performanceproducts.com/productpage.aspx?pid=105048&name=Power%20Bleeder
It work's much better that the mini vac style bleeders, just remember to zip tie your fluid reservoir to the master cylinder before using a power bleeder.

Mike Halleck
Chesterfield Mi
71 280SL
68 250SL (parts car)
94 E320 Coupe

[jsaylor]

Jeff/Mike...

Thier was an earlier post about brake bleeders which showed a home made model.  I made one with a garden sprayer and an extra break fluid cap.  Looks just like the one you show and works great.



Jim Saylor
Kauai, Hawaii
'65 230SL

[al_lieffring]

Over the years I have seen lots of clever one man bleeding systems, But it seems to me it would take longer to set them up than it does to just find a helper and do it by the old fahsioned pump the pedal and shout when ready method.

al  




66 230sl
113-042-10-014715
904/396 blue, Ivory Tex
condition: not-as-rusty-as-before-bucket

[Tom]

May take this project on over the weekend.  Please refresh my memory-start with the caliper furthest from the booster (passenger rear), then driver rear, then passenger front, then driver front-correct?

1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
1970 280sl Beach Driver with a touch of rust

[hands_aus]

Hey Jeff,
I just had my front brakes rebuilt using ATE parts.
They were working with no hint of a problem.
The calipers now have new pistons, seals, bleeders, hoses, pads, hardware.
The old pistons were like those in your pics.
I don't know how they could be resurected but I am sure someone could re-use them.

Just to be sure I had a new master cylinder and disks front and rear and 4 new Bilstein shock absorbers, front subframe mounts installed.

The car 'feels' a lot better on the road.

I had to have the rear brakes rebuilt 4 years ago, so I had new bleeder valves installed this time with an eye to the future.

Those pressure bleeders sure are attractive for a shade tree mechanic like me.

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[graphic66]

heres that link for the bleeder  http://www.bmw-m.net/TechProc/bleeder.htm  The thing really works great

[Vince Canepa]

One thing I see about the pistons in the last photo - the corrosion seems to be "outside" the seal, between the seal and the dust covers.  Annual flushing won't do anything for that.  I had the same problem on one of my rear calipers last year and they have been flushed at least annually.

However, I am a huge believer in regular flushing of the brake system.  I have been using an EZE-BLEED for years, but it is getting old and when I repalce it it will be with the Motive unit.  It takes all of one minute to pour in some brake fluid, screw the cap onto the reservoir and pump it up.

The problem with the old pump the brakes method is that it can lead to damage of the Master Cylinder seals.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[jeffc280sl]

Vince,

I think you're right.  Very good observation! I did have some rust inside the caliper piston socket but most of the problem was outside of the piston seal and between the dust seal.  Maybe the dust seal is a real culprit here and we should consider replacing it periodically.  I did install new dust seals as part of the caliper rebuild and found them very hard to install until I read about a tool MB describes in the BBB.  I made a version of it and the seals were much easier to put in place.

Jeff C.
1970 280SL 4-speed

[Naj ✝︎]

Jeff,

 

quote:I did install new dust seals as part of the caliper rebuild and found them very hard to install until I read about a tool MB describes in the BBB. I made a version of it and the seals were much easier to put in place.

Could you add a picture of the tool??

naj

68 280SL

[jeffc280sl]

Will do next time I get my camera out.

Jeff C.
1970 280SL 4-speed