NCV3 Replace Front Brakes

[piper1]

Decided to take the camera along in another Sprinter repair adventure.

Again, this is not a definitive "how to". Common sense and some general mechanical smarts are required but with time and patience, most should be able to do this. Take it slow and be thorough and it has a happy ending.

Some stats. I am replacing the original front brakes at roughly the 183,000 mile mark. The light on the dash came on finally. I had been anticipating this since October due to the condition of the rotors.

I replaced the rotors and pads. The rotors were well below spec thickness and were extremely rusted in the vent area. My braking performance was noticeably getting worse.

I got my rotors and pads from http://brakeperformance.com/

I purchased the premium slotted and dimpled rotors......mainly because I hoped they would improve performance......and they looked cool!

Parts arrived in good condition (last fall actually), as quoted and everything fit as good as the OE parts that came off. Customer service was pretty good too.

I did not...replace the sensors. They can be done afterward if needed without doing anything more than taking the tire off.

So...here we go.

 

[piper1]

With the truck jacked up and wheel off, here is what you see

 

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From the rear

 

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First step is to get the caliper pistons to retract. The shape of the caliper lends itself to this quite nicely. Using a large screwdriver of narrow flat prybar, insert the end into the rotor and pull outwards on the caliper body (moving it away from the vehicle).

Once you get it moved a bit, you can now pry between the rotor face and the inside pad to get it the rest of the way. Collapse the pistons fully into the caliper body.

** Some Cautions***

If you have ever topped up your brake fluid, remove the fluid reservoir cap before doing the piston retract..and don't be alarmed if fluid spills out of the reservoir, be prepared for it.

Good idea to wear safety glasses. There is flaky rust everywhere, rust that flies in odd directions as parts begin to move.

If the caliper does not move and the pistons do not fully retract STOP! Re-evaluate how you are doing this and if it looks OK, you may have a seized caliper piston. If you don't know how to deal with this...put everything back together, pump the brakes 5 or 6 times and take it to a professional.

Pry, evenly, top and bottom. You don't want one piston retracting way more than the other one!!

 

[piper1]

You can also pull out the sensor now, or before you start to pry.

The sensor can be pulled out with a pair of needle nose pliers. The connector end pulls straight out of the socket.

There is a small U shaped clip that may come out with the sensor...or it might stick in the pad. If you didn't get new sensors...don't loose this clip!

 

[piper1]

Remove the rubber boots protecting the Caliper slide screws. They will pop off but are very scared of sharp things!!

Remove the caliper slider screws. They are an allen head screw. They are not real big...and are likely rusted in place...be cautious. Snapping them off is a buzz kill.

 

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Screws

 

[piper1]

Have a nice sturdy crate or some other means of holding the caliper ready..you are going to remove it now and don't want it hanging on, or otherwise stressing the brake hose or sensor cable.

You may have to hit it with a soft hammer to knock it loose. There is likely a bit of rust between the caliper slide pins and the caliper bracket. Tap the caliper down then up..gently and it should break free.

 

[piper1]

Remove the old pads.

 

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The pad anti rattle clips or shims are clipped to the caliper bracket. If your pads came with new ones..replace them. They pry off and clip back on.

If you don't have new ones...just wipe them off with a rag, don't remove them. They are stainless spring steel and after bathing in all that brake heat, may not have enough spring in them to tolerate removal and then have enough spring to re attach firmly.

If you don't have them there, your pads will rattle and will drag, so be kind!

 

[piper1]

If you are not replacing your rotors...then skip down to "Caliper Assembly."

However...if you aren't replacing your rotors...are you sure you really want to do that?

I still had pad left, the rotors were trashed. It was the rotor ridge that triggered the brake light...not the pads.

My 2 cents.

You need to remove the caliper bracket next. 2 big bolts hold it to the steering knuckle.

They are quite tight!

 

[piper1]

Remove the rotor hold down screw (again, be gentle it isn't big).

At this point you are likely going to have to hammer the rotor off the hub. Hit 180 degrees apart (or turn it half a turn between hits). It will take a fair bit likely to get it moving.

Did I mention Safety Glasses are a good idea?

 

[piper1]

Clean the hub of any loose rust. Again, dont go crazy here with a wire wheel or other abrasive.

If you remove too much material the brake rotor and your wheel will not properly center themselves and may lead to vibrations or wheel bounce.

A thin coat of high temp grease is a nice idea...skip the never sieze.

We are going to use this grease a bit later too. Its a good idea to have a tube (even if your new pads came with some.

I'm talking about grease like this http://www.permatex.com/products/au...ake_Caliper_Lube_Hi-Temp_Silicone_Formula.htm

 

[piper1]

Re-install the caliper bracket.

60 ft/lbs plus 40 degrees

Install the new pads.

 

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Caliper Assembly

We are going to do a bit of work on the caliper pins. Caliper pins that do not slide freely can result in dragging brakes and uneven brake wear. Like the rest of the truck...MB saved a few pennies by putting very little grease on the pins.

We are going to remove them, inspect them and grease them properly.

 

[piper1]

The pin is held in by the rubber boot resting in a groove in the pin.

Carefully pry the boot out of the groove (nothing sharp!!) and push the pin out the pad side of the caliper.

Have a good look at these pins. If they show anything more than superficial rust, replace them. They should float freely in the caliper but not be sloppy.

Inspect the boots carefully. They are fragile and if torn need to be replaced.

Lube the pin up, put some grease in the caliper where the pin slides and carefully lift the boot back over the pin, push the pin back into the caliper and, re seat the boot in the pin groove.

You may choose to ignore this part of the job....but if you want to do it right....

 

[piper1]

Push the slider pin in all the way.

Lift the caliper back on to the caliper bracket and over the new pads. Make sure the brake hose is not twisted in any way!!

Install the slide screws.

Re install the sensors. With that little U shaped clip on them, they can be pushed back into the outer pad the same way you took them out. Reconnect the socket.

If your screws are M8 (small ones like mine) torque to 34 N-m (around 25 ft/lbs)

If your screws are M10 torque to 65 N-m (48 ft/lbs)

After you tighten the screws, put a bit of grease in the protective caps and install them.

 

[piper1]

Reach into the truck and slowly push the brake pedal down in short strokes. It will take 5-10 strokes to get back to a firm brake pedal.

Check for leaks and that everything looks as it did before you started (except for the new parts!)

Check the brake fluid level.

Re-install the wheels and torque to 177 ft/lbs (steel wheels)

Start the truck, check for firm pedal feel and go for a road test on some slow streets.

Try to let the brakes seat in with a few easy stops before you really get on the pedal.

Re check the brake fluid level.

 

[HSS]

Very nice instructions, thank you.

 

[shanemac]

Nice job piper....I was curious which brake pads you went with the standard ones that come with rotors or did you pop for the premium pads? Right now just debating which is better.