Frequently Asked Questions - FAQ's
"Generally" our turn around time is 3-5 working days for steel calipers. It can be longer if we need specialty kits or custom pistons that we do not stock. If you've elected to receive a core caliper for your car, it can be as little as one day to one week. All of these lead times are based upon inventory and current backlog in the build and assembly que.
For aluminum calipers, it can be 3-4 weeks depending on how much work it takes to get the caliper bodies in shape and, what our current backlog is. Each caliper undergoes extensive processing to get it back to where it needs to be. Because aluminum calipers are unique, we do not have cores available to swap. Once they go through over 8 steps of hand polish, they are then sent off for specialty anodizing which can take 10-20 days.
There are a few things that affect brake performance and reliability. The first would be; how long the car has sat? Brake calipers do not like to sit. The bore surface can build up rust and corrosion from the hygroscopic nature of the fluid. Moisture can get drawn in through the atmosphere when the brake system cools down, when it sits, it gathers around the rubber seals and this is where your plating has eventually worn off the bore (yes, the bores are plated). This can only be resolved with a complete restoration of the caliper. The hydraulic seals can also lose their elasticity after cycling the piston thousands of times and, the rubber dust boots can deteriorate over time with the heat generated during braking. The second would naturally be; how often was the fluid changed. If fluid can break down with the extreme heat "and" it's hygroscopic as described above, you can naturally see the need to change it every year. Now, we’re going to be like your dentist and pester you to make sure you change your fluid annually, "especially" if the car was never driven or driven lightly. An active brake system can generate a great deal of heat. That heat will normally boil off atmospheric moisture. If the car hasn't been driven, moisture and rust begins to take over.
The zinc plating we offer "is" the original appearance the calipers would have possessed as your car rolled off the assembly line.
Notice the worker is assembling a vented rotor T-Strut (black Boge with 3" mounting ear spacing and a stack of front M-Calipers). Notice not only the color but the variation of the zinc finish on the new calipers.
Generally, no. This phenomenon is well known and actually explained in the factory manual.
The bore seal is responsible for pulling the piston back into the bore. The seal journal is slightly tapered which allows the seal to rock back and forth. New seals will act more aggressively than old seals. Your new seals are pulling your pistons back into their bore further than they had before. Even a few "thousands" of an inch can cause excess pedal travel. The standard venting clearance should be around 0.004" which is basically the thickness of a business card.
There are two procedures you can do to help bring your pedal back up:
1. Get a "decent" pedal by bleeding all of the air out of the system. We have a great article here on how to bleed your system: https://pmbperformance.com/pages/gravity-bleed. 914 guys and gals may want to try a pressure bleeder and an assistant method. Once you get a decent pedal, bed your pads. Even old pads can be re-bedded allowing them to work much better than before. We have a great article on "Bedding" here. Once you're done with the bedding process, you should have a much higher pedal. We always like to recommend doing a final bleed on the brakes prior to hitting the track. A good road workout can help dislodge air bubbles trapped in your system.
2. Remove the current pads from your calipers. Using an old brake pad backing plate or a piece of 1/4" plywood etc. Hyper-extend the pistons in the pad cavity and then push them back into place. This act can help lubricate the new bore seals and prevent the pull from the new seals.
Over time, your seals will continue to break in and your pedal will be firm as before.
Please package the calipers properly. If possible, use the inner boxes your calipers came in to send them back. While the outer box may still look good and can be reused, we generally recommend against that. The medium and Large "Flat Rate Boxes" from the USPS are free of charge.
Please be aware, your cores will be used to fulfill another order so they "must" be complete and in restorable condition. We are "extremely" fair on core refunds and, on average, we usually only decline, 0.5 cores per year. That said, here are some things that will hit your core deposit:
- Broken or missing caliper body parts
- Missing, wrong or damaged fasteners
- Excessive corrosion (deep pits that make them undesirable for the next customer)
- Missing pistons
- Tool marks (hammer indents, cutoff wheel gouges... we've seen it all)
- Wrong calipers (E.G. 356 calipers vs. standard 911/912 L-Calipers)
As mentioned above, we are fair in our assessment of the cores. A missing or incorrect fastener will be charged for that one unit, not the entire core etc.
Would the rebuild price be less if I choose not to replate?
We do not rebuild calipers without zinc plating. It is not a cosmetic step in the process. It is the most "important" step in the process.
Without the zinc coating, the calipers would be gone by now. Without re-doing the zinc coating, they are in jeopardy for future longevity.
The most important step is getting the bores replated as this is what causes rust and stuck pistons. Over time, the pistons movement wears a section of the zinc off. Brake Fluid is hygroscopic meaning; water will enter the system and mix with the fluid. Water likes to gather around rubber seals. Your vintage car sits, your bores begin to rust and pistons stick.
NOT PLATING YOUR CALIPERS IS THE MAIN CAUSE OF CALIPER FAILURES!
Do you work on my calipers and return the same?
We can, and, in some cases that's a "must". Extremely rare calipers and aluminum calipers are generally all done using your specific cores. Some examples of calipers which would have to have your cores to complete are; Porsche 356, Porsche 914-6 rear calipers, Ferrari 308 front and rear calipers, early and late Porsche 930 calipers, all forged aluminum S-Calipers, early (67-68) Porsche 911S and L rear Wide L-Calipers.
We attempt to stock and can build out many stock steel calipers from Porsche 911, 914, 911SC and 911 Carrera through 1989.
First, let's make sure we get the directions for each adjuster down pat:
Outer Adjuster:
Clockwise - Pulls the piston (and pad) in and away from the rotor.
There can be multiple points of failure in your hydraulic system however, let’s start with the easiest and the least expensive options, your soft lines. Let’s start with some basics so you can understand what might be going on in your brakes hydraulic system. First of all, the system is “open”. There are usually one or two small pin holes in the brake fluid reservoir cap. This allows air into the system and in most places, that air has water in it… humidity. Brake fluid is what they call “hygroscopic” meaning, it attracts and absorbs water. That water likes to gather around the rubber seals in your system, be it the calipers, the master cylinder and/or the rubber lines. With miles of use, the zinc plating wears off the inside of your calipers and, that moisture converts to rust which locks up your calipers. This is why you sent them in. Your lines have also been sitting with old contaminated fluid in them for years and years as well. They begin to break down and swell internally. When they do this, higher pressure from you applying the brakes through the master cylinder, can force fluid out to the calipers. With the line being nearly swollen shut, that fluid pressure won’t return as fast as it went out. This is when we usually see odd behavior with various calipers acting differently than their counterparts.
My rule of thumb with soft lines is this; “If you don’t know when the last time they were replaced, replace them”. They are fairly inexpensive and will go a long way toward making sure the rest of the brake hydraulic system is up to snuff with your new calipers. The other rule is; “Every ten years”.
Bottom line; old brake soft lines can swell internally causing brakes to bind and lock and act funny. If the inside of your calipers were old and crusty, the inside of your lines will be the same.
Couple of things:
1. The 914 hub is basically designed for a 914 CV which is the same as a VW Beetle (Type 1) CV joint. The spline count only allows a 914-4 stub axle that only fits that CV. The CV will fail LONG, Long, long before the hub will ever fail. In fact, I've "never" seen a drilled hub fail. It would take a whole ton of torque to do something like that.
2. By drilling (vs. spot facing and pressing in), we feel the hubs are actually stronger. When you spot face a -4 hub for 5-lug, the final thickness is only 3mm at the seat where the stud is pressed into the hub. Drilling retains all of the hub material and offers more thread/stud engagement. These are stronger than press in stud models.
Drill it out.
First, let's delve into "why two different size pins"?; In order to understand the fat pin, skinny pin scenario, we need to look at the top of your piston. Notice these pistons have a flat top (no pad angle grooves cut into them). Your front calipers have pad grooves cut into the piston tops so the pads open up in the face of the oncoming rotor (Hold your hands like you are praying. Now open your fingertips). Due to the nature of the rear caliper design, these pistons can spin as they progress and the handbrake is applied so, a fixed groove to open the pads will not work. Engineers solved this problem by creating a special "bevel" in the pad material. To ensure these pads were installed with the bevel in the proper direction, they made it so the pads could only be installed in the proper direction by mating the pad plate with the proper size hole in the caliper.
Now, why do I have to drill out my pad plate?; 914 pad sizes are extremely common (D30 for the -4 and D31 for the -6), 914 rear calipers are not so common. Over the years, pad manufacturers have dropped the beveled pad and the odd pin sizing for the extremely small market with these esoteric pads.
Is it a big deal? Not really. If you follow the bedding procedure on the site here you should be rather noise free and you should sill get good consistent, even pad wear.
Bottom line; drill it out. You can use a 9mm or a Letter Size "T" or simply any 3/8" bit from your local hardware store. Put the pad in a vice (they will catch and chew up your hand or break a finger) or in a clamp in the drill press. Drill two pads with larger left holes and two with larger right holes.
Why do I see two different prices on many of your caliper restorations?
We get this question a lot. The different prices on the product page vs. the overview page can be explained as the difference in the "core pricing".
The core charge, sometimes called a core price, is a form of deposit you pay until returning your old calipers. If you don't have the core at the time of purchase, you must pay the core charge. That charge is refunded to you when you return the core.
On the product detail page we explain this as well: ***PRICE IS PER PAIR. IT INCLUDES A $XXX CORE CHARGE THAT WILL BE REFUNDED UPON RETURN OF YOUR USABLE CORES***.
That said; if you plan on sending your calipers in for restoration and, you're getting your calipers back, there is no core charge.