VWVortex.com - Caliper rebuild questions
Username or Email Address
Do you already have an account?
Forgot your password?
  • Log in or Sign up

    VWVortex


    Results 1 to 6 of 6

    Thread: Caliper rebuild questions

    1. 05-17-2019 10:52 PM #1
      I am rebuilding my front calipers. They are the K-H type from a '84 GTI with vented rotors.

      These have two guide pins (sliders) per caliper; a shorter one and a longer one. I want to replace them but I notice many vendors only list the longer guide pin for sale (see picture below). Looking at them, I see no reason why the longer ones couldn't be used for both sides on each caliper (i.e. four long ones instead of two long and two short). It will just stick out a bit at the exposed end. Seems like the rest of the hardware (plastic and rubber sleeves) will work the same regardless.

      Anyone have more info on this?




      Also, the old rubber sleeves that these guide pins ride in have deteriorated into a very sticky goo. What a huge mess it makes. Has anyone found a neat way to get all of that tar like slime off? It will eventually come clean but it is slow and a real pain to do.

      Thanks, Jeff
      Last edited by Dr.Jeff; 05-17-2019 at 10:57 PM.

    2. Remove Advertisements

      Advertisements
       

    3. Senior Member briano1234's Avatar
      Join Date
      Feb 20th, 2004
      Location
      Atlanta Ga
      Posts
      20,486
      Vehicles
      90, 92, 93 Cabriolet They own you.
      05-18-2019 06:58 AM #2
      Quote Originally Posted by Dr.Jeff View Post
      I am rebuilding my front calipers. They are the K-H type from a '84 GTI with vented rotors.

      These have two guide pins (sliders) per caliper; a shorter one and a longer one. I want to replace them but I notice many vendors only list the longer guide pin for sale (see picture below). Looking at them, I see no reason why the longer ones couldn't be used for both sides on each caliper (i.e. four long ones instead of two long and two short). It will just stick out a bit at the exposed end. Seems like the rest of the hardware (plastic and rubber sleeves) will work the same regardless.

      Anyone have more info on this?




      Also, the old rubber sleeves that these guide pins ride in have deteriorated into a very sticky goo. What a huge mess it makes. Has anyone found a neat way to get all of that tar like slime off? It will eventually come clean but it is slow and a real pain to do.

      Thanks, Jeff
      Find the short ones, they are better that way.
      The GOO is best cleaned with either Brake clean and a rag, then wd-40. Finish by polishing the pins with 600 wet or dry sand-paper, as they really don't get worn unless your bushings have allowed them to hit the caliper metal.

      The later type of Vented Calipers use a different Bracket, and teh slides are threaded and still available. Look at a 90-93 Cabriolet.

    4. 05-18-2019 09:08 AM #3
      Using petroleum products on rubber brake components can cause real big issues. WD40 is a no no in my book. If you are taking apart the entire caliper and replacing all the seals, maybe, but then you need to spend the time/money buying the product to remove the petroleum product.

      There was a tread recently about what brake paste to use and some were upset that the brake paste they were using was swelling up the rubber seals. That is because if you looked at the label, it was not designed for the rubber brake components.

      If you are completely tearing the caliper apart for a true rebuild and you are using regular solvents to clean those parts up, clean the parts off with water and then some alcohol. Be extremely careful if you working around master cylinders. Cleaning the inside of the reservoir with the wrong product can really screw up the internal seals of the cylinder. I had one mechanic that had a lot of comebacks with master cylinder issues. Come to find out, he also used a lot of brake clean during a brake flush.

    5. Remove Advertisements

      Advertisements
       

    6. 05-18-2019 01:22 PM #4
      I will be doing a complete rebuild on them, replacing all of the seals, boots, hardware, etc. I usually start by cleaning them externally with solvent before disassembly to get as much of the crud off first. Then tear them down completely and do a better cleaning. I will be sure to rinse all petroleum products off before reassembly. But that thick black tar goo is a real bitch to get off. And it sure makes a huge mess of everything. I think I'll be having nightmares about it attacking me in my sleep.

      I saw that discussion about the silicone lube reacting with the rubber. What seems strange is the large rubber boot around the piston, and the two small rubber boots that go over the guide pins (rears), and the seals themselves are never affected at all...only the rubber sleeves that go between the guide pins and the front calipers. And I've not noticed anything this bad on all the other old vehicles I done over the years. Seems this dissolved rubber is somewhat unique to not only these VW calipers, but to these particular pieces at the guide pins. I've had the exact same thing on all of the old VW calipers I've ever done. Strikes me odd.

      As to the long vs short guide pins. First, I want to replace them due to the hex drive ends being damaged/stripped from previous people working on them. And second, to make the clean up job a little easier (I'd rather replace them than deal with more of the goo). Third, I already have several of the longer pins on hand as a result of them being what is in stock every time I go to buy some. So hopefully someone can tell me WHY the longer ones should not be used in place of the shorter ones. Sorry, but just saying "they are better that way" really does not help. How will having a little extra sticking out of the back (the end that is exposed, where the wrench fits) affect any thing? The sleeves will be the same, and everything from that point forward will be the same. It will only be the bit outside that's extra. I can't see where this will make any difference on their function. But maybe I'm missing something?

      Thanks for all input, Jeff

    7. Member mokoosh's Avatar
      Join Date
      May 26th, 2009
      Location
      2/5 of the Way from San-Fran to Port-Land
      Posts
      594
      Vehicles
      82 Rabbit Pickup 1.9D, 82 Jetta 1.9D, 06 MK4 Golf TDI, 2 81 Diesel Sandstone Caddys, 80 5DR
      05-19-2019 09:57 AM #5
      If I remember correctly, I ended up using all long pins last time. I certainly remember having the same thoughts and I don't see any reason not to use them except possible exposure to the elements if they stick out past the rubber boot. Seems like the main issue is keeping them greased up and sliding smoothly. I think sticky pins often get diagnosed as a bad caliper.
      Quote Originally Posted by rabbitnothopper View Post
      facebook...pfft. vwvortex baby!

      The NONSMKR

      perpetual online swap-meet(V2.2 FS: Early Rabbit Tails)

    8. Yesterday 01:49 PM #6
      Here is my thought on the extra portion of the long pins being exposed.

      Normally using the regular length of pins (i.e. short and long), when the pads are new the rubber sleeve covers all but the very end of the pins as you said. Then as the pads wear and the two halves of the caliper gradually migrate closer together, the pins will be exposed more and more out of the rubber. So eventually some of it will be exposed anyway. And that exposed portion will not go back into the rubber sleeve until new pads are installed to move the caliper halves back away from one another. I think that is one good reason for replacing the pins when new pads are installed, if that exposed portion became corroded.

      In the case of using the longer pins in place of the normally shorter ones. Even when the pads are new, there will be more exposed area outside of the rubber sleeve as you stated. But as the pads wear that portion of the pin only migrates further out of the rubber - not inside of it. So even if it gets corroded it will not matter. It might make them more in need of replacement the next time the brakes are redone, but as I mentioned that may be the case anyway because even the normal length pins get exposed eventually.

      As for the pins moving back INTO the rubber sleeve. Yes it does slightly when the caliper "floats" during usage. But only within the rear most portion of the rubber sleeve's extension that is beyond the caliper. The pin never actually travels far enough in that direction for the exposed end of it to make contact with the actual "sliding" surface portion. So in the event the exposed part of the pin eventually becomes corroded it will not matter, it just moves around in the non-critical area of the rubber. That is the reason for the rubber sleeve to extend that far out in the first place.

      Furthermore, in my case I am located in a extremely dry climate where corrosion is very limited. And I rarely drive this vehicle so one set of new brake pads will likely last the life of it (at least as long as I own it). So I'm really not too concerned about the exposed end of the pins getting corroded or having to replace them often. But I realize that is somewhat unique to my situation. What I am concerned about is if using the longer pins in the short position will cause any other problems. I cannot think of any but maybe someone else can?

      This is my understanding anyway. Please add more insight to something I've missed or am wrong about.
      Thanks, Jeff

    Similar Threads

    1. Caliper Rebuild Question
      By talguy in forum Brakes
      Replies: 2
      Last Post: 11-11-2014, 11:01 AM
    2. Replies: 3
      Last Post: 04-14-2014, 02:42 AM
    3. Caliper Rebuild Question
      By loligagger in forum Brakes
      Replies: 2
      Last Post: 07-10-2012, 02:36 PM
    4. Wilwood caliper rebuild questions
      By Mr Black in forum Brakes
      Replies: 4
      Last Post: 10-15-2003, 06:20 PM
    5. Replies: 4
      Last Post: 04-20-2003, 02:31 PM

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •