How To Replace Your Seized Front Brembo SRT Caliper Pistons
DISCLAIMER: THIS IS TO ONLY BE USED AS A GUIDE TO COMPLETE THE SAID REPAIR. I AM NOT RESPONSIBLE FOR ANY DAMAGES THAT YOU MIGHT CAUSE TO YOUR VEHICLE OR YOUR’S OR ANYONE ELSE’S PROPERTY BY FOLLOWING THESE INSTRUCTIONS, ANY INJURY, OR DEATH TO YOU OR ANYONE ELSE WHO MAY BE HELPING YOU, AS A RESULT OF FOLLOWING THESE INSTRUCTIONS.
IF YOU HAVE LITTLE OR NO EXPERIENCE IN CONDUCTING MAJOR REPAIRS ON BRAKING OR OTHER VEHICLE SAFETY CRITICAL COMPONENTS, IT IS BEST TO LEAVE THIS TASK TO A PROFESSIONAL MECHANIC.
Because I've also posted this at other forums, I know that here @LXforums, admins would like to see pictures before article submission.
However, during the course of this repair, it proved to be extremely difficult to take photos, as the nature of handling lubricants and brake fluid warranted me not to touch my camera equipment, so I apologize for the lack of photo's.
I do believe I have made up for it, in the detailed descriptions/instructions of this article, and hope that it may be of value to forum members.
Established in Bergamo, Italy in 1961, Brembo S.p.A. is a manufacturer of automotive brake systems. Brembo Brake products, are world renowned for their superior braking capabilities, longevity, and quality workmanship. As such, automakers of BMW, Chrysler, Lancia, Mercedes-Benz, Nissan and Porsche, have chosen Brembo to equip their top end models with this braking system.
Unfortunately, there seems to be an exception to the rule when it comes down to many Chrysler SRT vehicle lineups. The Brembo braking systems in these vehicles, do not seem to be up to par with their cousins that are fitted on Mercedes, Porsche, BMW etc. Many Chrysler LX Owners have reported corrosion and seizure of the front inboard caliper pistons, as early as their first brake pad change.
Also of note, is the fact the the rear pistons of the Brembo system in Chrysler vehicles, are of a hollow design, which do not seem to be affected by corrosion, as the front calipers are.
With the official word of Chrysler Service manuals, these calipers are not serviceable, with the only remedy being the replacement of affected Calipers with new units. (roughly to the tune of $800.00 or more per unit)
Also, despite to rising number of affected Chrysler vehicles, Chrysler has chosen not to address this issue past a given Chrysler vehicle's warranty. In short to them, the issue does not exist.
HMMM.... Not Serviceable.... Well, David Zechhausen Racing, Stoptech, and Centric, beg to differ. you can rebuild ANYTHING as long as you have the right parts to do it! Let's move on shall we?
4 X Stoptech 44mm caliper pistons P/N 41.544.0001 Available from Zeckhausen Racing here:
2 X Centric Caliper rebuild kits P/N 143.63003 Each kit has four pressure seals and four dust boots for one caliper. Available from Zeckhausen Racing here:
TOOLS AND SUPPLIES NEEDED:
Breaker bar (the 2 caliper bolts are fairly tight)
Torque wrench (always a good idea to torque brake components properly)
21mm socket (Caliper bolts)
15mm box end wrench (banjo bolts)
11mm box or open ended wrench (bleeder screws)
Small flat bladed screwdriver or similar tool (to pry out old pressure seals)
Brake assembly lube (you must get this if you don’t want to wrestle with your new pistons- new seals are tight)
A can of Brakekleen, or other type of brake cleaner of your choice.
1 to 2 liters of DOT 3 fresh brake fluid (you’re going to lose some)
Lots of shop rags (brake fluid messy- need I say more? Also caliper paint is not impervious to brake fluid contrary to popular belief)
A large pan or container (put this underneath the spindle assembly to catch any stray fluids, when removing caliper from wheel assembly)
Pair of jack stands and a floor jack.
A piece of fine emery or crocus cloth that you can cut into smaller pieces.
A 1 ½ inch long quarter inch in diameter nut and bolt (to be used on banjo fitting to stop the flow of brake fluid from the system)
2 or four pieces of ¼ inch thickness wood cut roughly in the shape of the brakepads. Balsa
wood works great as it is soft enough to be cut by aviation shears, but you can choose anything you like. Basically these will be used to:
A) Protect the rotors from pistons that are rising out of the bore
B) Prevent pistons from fully popping out of the bore, and minimizing brake fluid mess.
If you are using another method to force pistons from their bores such as compressed air you probably don’t need these. Exercise extreme caution when using compressed air. As little as 30 psi can send a piston across a room or into someone’s face.
LET'S GET DOWN TO IT:
This is best done in a garage or sheltered area. It should take about three to four hours to complete if you take your time, and use care to do it right .
Loosen, but do not remove wheel lug nuts.
Raise front of vehicle and remove front wheels. Turn the steering wheel in the opposite direction of the side you are working on. This will give you better access to the inboard side of the caliper that you are working on.
Using a punch and a small hammer, tap out the brake pad retaining pins. Note the orientation of the spring clip brake pad retainer for later assembly. Also make sure that the brake pads don’t go on backwards during assembly. (yes they can fit that way, and your rotors won't like it)
Inspect the inboard and outboard pistons. If you cannot push them into their bores, and they look corroded, chances are they are seized.
It’s almost always the inboard pistons that are seized. You can choose to change only those if you wish; I chose to replace all of them as I think it’s important for all pistons to share the same physical, metallurgical and chemical properties. This guide assumes replacement of all four, and also assumes only inboard piston seizure. If your results are different you can improvise by using this guide.
Remove ONLY the inboard brake pad-leave outboard pad in place. Insert one of the wooden shims into the brake pad slot where you removed the pad. This should provide enough head room for seized pistons to break free once you apply brake pedal pressure, and will protect the rotor.
Get into vehicle and pump the brake pedal as hard as you can. Eventually you will hear the seized pistons start to creak out of their bores. Get out of the vehicle and inspect the pistons to see how far out they have come. Repeat the process until both inboard pistons are touching or resting against the wooden shim. This should give you enough piston area to work with during removal process later.
Now remove the outboard brake pad and insert another wooden shim. Remember these are not seized, but you want to raise them out of their bores as well. Just pump the pedal in small increments until one, or both of them have come out just enough for you to be able to get a grip on them. Try not to let them retract all the way to the wooden shim. Pump-inspect-pump-inspect. You need to leave a bit of slack so you can remove the caliper assembly from the steering knuckle.
If only one(non seized) piston has risen, you can push it in with your fingers to cause the other to rise out of its bore. Fluid dynamics at work here fellas.
Once you are satisfied that all four pistons have risen far enough out of their respective bores to get a good hold of, you can remove the caliper by loosening and removing the two 21mm caliper to steering knuckle bolts. These are on tight. Use a large drive or breaker bar.
Loosen bolts but DO NOT remove caliper until you have removed the 15 mm banjo bolt that secures the flexible brake line to the caliper. The banjo fitting has two brass washers on either side. Do not lose them. In fact now would be a good time to use a small ¼ inch in diameter nut and bolt small enough to fit through the banjo fitting. This will prevent the draining of your master cylinder, which if should occur would surely constitute in you having a very bad day. You would have to bleed the entire system(all four wheels) Snug this on-tighten just a little bit to stop fluid from leaking.
Remove the caliper and loosen the bleed screw. This will allow you to drain most of the brake fluid from the hole where the banjo fitting sits (you’re wearing rubber gloves, right? Brake fluid is toxic)
Once you are satisfied that most of the fluid is drained, tighten the bleeder screw and insert the banjo bolt into the opening to close the hole.
Clean the caliper assembly thoroughly with brake cleaner, and wipe dry. Remove the banjo bolt from the caliper, and loosen the bleeder again to allow air to be drawn in during the piston removal process, otherwise the vacuum will make piston removal impossible.
If you are working on a bench, use a liberal amount of shop rags on your work area- when pistons are removed, more fluid will spill. Promptly wipe any brake fluid from caliper painted surfaces.
Set your caliper on the rags on top of work bench. Using a small flat bladed screwdriver, or equivalent small prying tool on the outer edge of the dust boot, carefully lever it out, and pull the surround off the piston.
Grab the piston with adjustable jaw pliers on the outer top edge as you would a pipe with a pipe wrench, and twist it back and forth, While pulling at the same time. Depending on the amount of surface corrosion, this may take some effort. There is also a special extraction tool sold by Genesis technologies designed exclusively for 44mm pistons. The part number for this, is GT5185, and the cost is $41.95 Credit to Dave Zeckhausen it can be seen here: (ignore the part numbers on photo)
If you are interested in this item, contact Genesis Technologies directly at (888)285-8090, or see these on their home page here:
Genesis Technologies Racing Brake Caliper Piston Removal Wrenches: Genesis Technologies Race Car Parts and Equipment
Because it is assumed that we will not be reusing the old pistons, you can use adjustable jaw pliers but be aware that the teeth on the pliers WILL damage the surfaces of the old pistons.
DO NOT UNDER ANY CIRCUMSTANCES USE PLIERS ON A PISTON IF YOU ARE PLANNING TO RE USE IT!
ALSO DO NOT PUT ANY PISTON INTO SERVICE THAT HAS BEEN SUBJECT TO THIS KIND OF REMOVAL!
Alternatively you can use a flat punch on the groove at the top of the piston, and hammer it lightly. This will cause the piston to tilt slightly in its bore, which will cause it to bind, so flip over the caliper and hit the piston again 180 degrees from the previous striking point. This will cause the piston to slowly drift out of its bore, and eventually pop out. You may have to flip the caliper three or four times, until the piston breaks free. You may also see some fluid from the bore when the piston is out. Wipe any that may have spilled onto caliper surface.
USE A PRYING TOOL, AND REMOVE THE PRESSURE SEAL FROM IT'S RACE. SLIDE THE TIP OF THE TOOL UNDER THE SEAL TO POP IT OUT. BE CAREFUL AND TRY NOT TO CUT, KNICK OR PIERCE THEM! EVEN THOUGH YOU HAVE NEW SEALS TO REPLACE THEM, THERE IS A SMALL CHANCE THAT YOU MAY BE REUSING ONE, OR MORE OF THEM! MORE ON THIS LATER.
Now inspect the top inner part of the bore. You will definitely see some white galvanic corrosion marks that have affected the black coating of the bore. The corrosion will have to be blended out.
Cut a small piece of shop rag and insert it into the bottom of the bore to prevent any debris from settling into the bottom of the bore, from what we are about to do next:
Take a small piece of emery cloth and work this area in a circular motion around the inner top of bore to blend out the corrosion. Use a new piston to test the bore. Do NOT insert pressure seal at this time. Slide the piston in and out squarely to make sure it isn’t binding. If the piston won’t move relatively freely against the top inner bore, rework that part of the bore with emery or crocus cloth to smooth out any remaining corrosion.
Although this is an effective method in blending out the corrosion, it will also blend out some of the black protective coating of the bore. There is nothing that can be done about this, as this area of the bore is already deemed damaged by the corrosion itself. Hopefully further corrosion can be slowed down by the dust boot ,brake assembly lube, and the fact that the new pistons are anodized, which could prevent future galvanic corrosion in this area.
DO NOT I REPEAT DO NOT UNDER ANY CIRCUMSTANCES use crocus cloth further into the bore ESPECIALLY in the area where the pressure seal sits, or beyond that depth. Only blend out any affected area in the top inner part of the bore.
Keep test fitting the new piston until it slides in and out of the bore freely. The tolerances are pretty tight, so make sure you are holding the piston squarely as you insert it and slide it in and out. If you don’t hold it square it will bind a bit. This is normal, and not to be confused with the binding caused by uneven surface as a result of the corrosion, which will bind the piston no matter what.
When you are satisfied that the bore is ready, clean it out with a small amount of brake cleaner, and remove the small piece of cloth from the bottom of the bore. Do this carefully, as to not allow any debris from falling back in- hold the caliper upside down while doing this so any debris will fall OUT of the bore. Give it a good final wipe with a clean cloth dabbed in brake cleaner.
Test fit the piston again for good measure. If all seems well, it’s time to reassemble that bore. Use a liberal amount of brake assembly lube on the pressure seal, new piston surface and the race where the pressure seal sits into. Guide the seal with your fingers until it slides into the race and is seated properly. Run your fingers over it to verify.
Slowly insert the piston squarely into the bore. It will show some resistance when it reaches the edge of the seal. Pump it gently with your fingers, and it will eventually slide past it.
DO NOT LET PISTON GO ALL THE WAY INTO THE BORE YET. ONLY JUST ENOUGH TO MAKE IT PAST THE PRESSURE SEAL. IF YOU DO THIS, IT WILL BE DIFFICULT TO FIT THE DUST BOOT OVER THE PISTON GROOVE.
MAKE SURE YOU USE ASSEMBLY LUBE- NEW PRESSURE SEALS ARE VERY TIGHT AND IF YOU INSERT THE PISTON IT WILL BIND AND NOT MOVE AND POSSIBLY DAMAGE THE PRESSURE SEAL, WHICH WILL REQUIRE EXTRACTION OF THE NEW PISTON TO INSPECT FOR POSSIBLE SEAL DAMAGE AND REPLACEMENT.
Now take a new dust boot, and fit it like a sleeve over the groove over the top of the piston. Using fingers from both hands push the outer retainer of the boot onto the top of the bore until it clicks into place for a lack of a better word. Let’s move on to the next piston:
Repeat the process for the next seized piston.
The other two pistons which are not seized will be much easier to remove, and you will not have to blend out any corrosion. The rest of the piston installation instructions, are the same- just repeat the process. Once you have completed the entire caliper rebuild, make sure you push new pistons ALL THE WAY into their bores BEFORE you hook up the brake line in the next steps:
You don’t want to assemble the caliper, pads and rotor only to find out that something went wrong, and the pistons did not seal correctly, do you? That would be unfortunate. So here’s how we are going to test it:
Install caliper onto steering knuckle, and hand tighten the bolts- remember we are testing, not final assembly yet. Install banjo fitting and tighten to 24 ft lbs.
(Did I mention the part about pushing the pistons ALL THE WAY in BEFORE hooking up the brake line?)
Insert the brake pads. You do not need to insert retainer or pins. Bleed that caliper using the manual bleeding method, and an assistant to work the pedal.
I won’t describe bleeding technique, as you probably already know how to do this. Just remember to not let the master cylinder go dry, and that the caliper has a LOT of air at this point.
You may have to bleed excessively to make sure ALL the air is out. Use a rubber mallet to tap the calipers. this will force air bubbles to rise towards the bleeder screw. I had to bleed them twice.
Once the caliper is properly bled, press hard on the pedal, and hold for a few seconds. If you bled it properly it should be pretty stiff. At this point, if the seals were not installed properly, or the pistons damaged the pressure seals going in, trust me-you would know about it. you'll feel the pedal collapse, and you'll have brake fluid all over the place. Remember, work that pedal hard to remove all doubt. Again make sure you have properly tightened the banjo fitting, or you'll get a false positive. If the pedal remains stiff, and you don't hear fluid leaking, you should be OK.
Having said that, remove the pads and inspect the dust boots. If any of them appear to be swollen in any way, and you find evidence of brake fluid dampness around any of the swollen dust boots, then that particular piston or pistons, have to be removed again. If any the pressure seals are damaged, you can use some of the old ones, providing they are in good shape, and you did not knick cut or pierce them during the removal process. If in doubt, best to order new ones again.
If all is well, assemble everything in the reverse order. Banjo bolt is 24 ft lbs, caliper bolts are 140 ft lbs and SRT wheel nuts are 110 ft lbs.
Repeat this entire process for the other side.
Once, you are ready to test drive, make sure lug nuts are properly torqued, pump pedal a few times to build up pressure. If repair was done correctly, you will experience much smoother braking progression, as the calipers are now clamping both sides of the rotors with equal force, during brake application.
Re-torque your lug nuts after 100 km's or 60 Miles.
Last edited by vyper883; 08-21-2011 at 07:26 PM.
300C... A Demon In Gentleman's Clothing...
300C SRT 8... Pure Evil Dressed to the Nine's...
"Ever notice how you come across somebody once in a while you shouldn't have ****ed with? That's me." Clint Eastwood as Walt Kowalski in Gran Torino.