AJP brake retrofit

Discussion in 'Trials' started by heffergm, Oct 9, 2018.

  1. heffergm

    heffergm Long timer

    Joined:
    Sep 22, 2014
    Oddometer:
    2,206
    Anyone know where I can get a complete AJP caliper and master cylinder setup to retrofit a modern GG pro? I've officially had it with Braktec.
    #1
    lineaway likes this.
  2. lineaway

    lineaway Long timer

    Joined:
    Oct 1, 2011
    Oddometer:
    8,769
    Location:
    nm
    Bitch of it is, you need a hose too.
    #2
  3. tomatoe333

    tomatoe333 Long timer

    Joined:
    Sep 25, 2007
    Oddometer:
    2,445
    Location:
    Back on the east side
    Did you check ajpamerica.com? I believe that's Jim Snell's web store for AJP parts.
    #3
  4. Norman Foley

    Norman Foley Devotee of the Husqvarna Supporter

    Joined:
    Mar 20, 2004
    Oddometer:
    2,283
    Location:
    New York... The Finger Lakes
    Stuart can't help you with this?
    #4
  5. motobene

    motobene Motoing for 46 years

    Joined:
    Mar 9, 2013
    Oddometer:
    5,326
    Location:
    Wichita Mountains SW Oklahoma
    Um, why?

    BrakTec and AJP are both 9.5mm diameter, both good stuff. BrakTec is a newer design that is considered one level up by BrakTec, which owns and makes AJP.

    Some BrakTec master cylinders 2014 to 2015 had too sharp reservoir refresh hole edges at the cylinder bore, which nipped the cup seals, but those are easy to make right with a few seconds of diamond honing.
    #5
  6. Hoss Cartright

    Hoss Cartright Been here awhile

    Joined:
    Oct 23, 2016
    Oddometer:
    623
    Location:
    Earl Park Indiana
    AJP did not pay employee withholding and other taxes. They owed the Spanish Government a lot of money.
    When they closed in early 2011, all the trials companies were left in the lurch. Subsequently, we had the 2012 "Formula" brand debacles.
    They were a rat hole operation on the third floor of a run-down office building in a sketchy neighborhood in an area of Barçelona known as El Prat de Llobregat. Sketchy enough that the cab driver had to call them for directions. "Go in the loading dock, take the elevator to the third floor, down the hallway, third door on the right."

    They did not answer emails, were not open regular hours, replacement parts were almost nonexistent.
    They were horrible for swarf and debris inside finished product, porosities, improper coatings, poor anodizing, incorrect machining, cross-threaded bolts.....

    Yes, AJP AMERICA is my website. http://www.ajpamerica.com/
    I spent almost one month building the site, taking every one of those images, naming the image files by the GG part number. At that time AJP had no corporate website.
    Before I built my site, there was no reference of dimensions or images for making comparisons.
    Before my website, all we had were crude drawings in parts books that were riddled with errors, making almost everything a shot in the dark. And I built the site for everyone around the world to use as a place to reference the specifics of the products.
    If you look at 1990s trials bikes, you'll typically see "j.juan" printed on the hydraulic hoses. J.juan was the hose supplier to the trials industry as well as other manufacturers of machines that had hydraulic systems.
    When j.juan won the AJP business (not much different than Torrot and GASGAS) we all breathed a sigh of relief.
    Braktec is the off-road division of the j.juan group. The production of AJP/BRAKTEC is located in the large and modern j.juan factory in Southwestern Barcelona near the airport. I've been there with Valerio Pastorino in 2013 just after the re-start and spent the day with them, went to lunch, and we discussed many things.
    They are OEM suppliers to all the Trials companies, as well as BMW and YAMAHA Europe. They also make systems for Bombardier Canada.

    Link http://jjuan.es/en/

    20181018_185626.jpg

    20181018_185639.jpg

    j-juan-1.jpg

    mapa de j.juan.JPG
    #6
    Nobade, Bounder and jonnyc21 like this.
  7. Hoss Cartright

    Hoss Cartright Been here awhile

    Joined:
    Oct 23, 2016
    Oddometer:
    623
    Location:
    Earl Park Indiana
    I've got every combination in stock, you will need a hose as the older AJP stuff is 10mm banjo, the newer stuff is 8mm.
    Stuart can take care of you, I can drop-ship to your door.
    #7
  8. motobene

    motobene Motoing for 46 years

    Joined:
    Mar 9, 2013
    Oddometer:
    5,326
    Location:
    Wichita Mountains SW Oklahoma
    So what were (are) your BrakTec problems? What year bike? As far as I know, all the ones I fixed are still working great.
    #8
    Norman Foley and fprintf like this.
  9. lineaway

    lineaway Long timer

    Joined:
    Oct 1, 2011
    Oddometer:
    8,769
    Location:
    nm
    Man I need to put mine back on my bike!
    #9
  10. Cascao

    Cascao Adventurer

    Joined:
    Apr 4, 2018
    Oddometer:
    83
    Location:
    Brazil
    Have two sherco trials. one 2010 with AJP brakes and one 2015 with Braktec.
    The 2010 with AJP have stronger front brake and lighter clutch.(S3 levers)
    Can I make the braktec work as good as older one?
    Seems like sherco returned to old design on clutch last year...
    #10
  11. Beatprojim

    Beatprojim Beatprojim

    Joined:
    Sep 2, 2015
    Oddometer:
    188
    Location:
    Acme, PA
    I am amazed a bit by how many components are interchangeable. Mr. Snell sold me an upgrade front brake kit (master cylinder and caliper) for my 2001 GasGas. This was just a buddy bike I keep around for friends and when my 2017 Sherco front brake showed signs that it needed a rebuild right before an event, I was happily surprised that the GasGas part fit perfectly to the Sherco Forks. That front brake system now lives on a 13 Sherco with that bikes brake system on the the 01 GasGas.
    #11
  12. fprintf

    fprintf Been here awhile

    Joined:
    Oct 24, 2017
    Oddometer:
    195
    Location:
    Connecticut, USA
    @heffergm it's a great question!
    #12
    Hoss Cartright likes this.
  13. Hoss Cartright

    Hoss Cartright Been here awhile

    Joined:
    Oct 23, 2016
    Oddometer:
    623
    Location:
    Earl Park Indiana
    Front brake caliper mounting configuration has been standardized since the mid-1980s. Some early 1990s USD Paioli and Marzocchi forks required small spacer washers to be placed between the caliper and the fork leg to get proper center-line alignment of the caliper and drake disc but this is it. From what I have seen, by the mid-1990s and the return to RSD suspension, all forks are made to accept the calipers and all calipers are made to the same mounting hole and brake disc offset specifications. So, yes, interchange is incredible among the brands.

    On that caliper subject;
    Spongyness and lack of a hard powerful feel can be not only air in the system, but flex of the two caliper halves as well as hose expansion and flex of the actual master cylinder on the handlebar and any combination of these factors.
    I would like to say that the old type AJP "two piston" calipers are actually quite good! This model and design first appeared in the mid-1980s on the first disc brake machines from Spain. Over the years they have improved the rigidity of the casting halves and improved production quality and they still produce them as they continue to be popular. (also Brembo and Grimeca made very similar and dimensionally interchangeable ones that were popular but I think are no longer produced. The Grimeca one was used on Beta machines and from my experience are not very good)
    I still import and stock the 2-piston calipers, pads, and all related repair parts as they are commonly used in the aviation and maritime industries and some trials people still prefer them as they work very well with few problems.
    And a variation of this same caliper is used in the retro-fit kit I sell to solve the inherent problems with the "HEBO" four piston rear caliper that was used by GG from 1999 through the Edition 03 2003 models of the TXT line. (not the Pro)
    These calipers are very rigid so they have minimal body flex which transmits a solid feel to the lever or pedal and they are powerful and reliable.

    BT27722000.jpg

    R260001.jpg

    DSC00351.JPG

    The problematic HEBO rear caliper that my above retro-fit "kit" replaces. Beyond the fact that the pistons seize inside the caliper, the hydraulic ratio of the master cylinder and rear caliper was wrong. Making the rear pedal travel way too long for effective braking. (These power and pedal travel factors are exactly why nobody is currently using a 4-piston rear caliper)
    BT27922001a.JPG
    #13
  14. tomatoe333

    tomatoe333 Long timer

    Joined:
    Sep 25, 2007
    Oddometer:
    2,445
    Location:
    Back on the east side
    I was just having a conversation with a member of my local club who just picked up a 2000 GG TXT 270, and was wondering what his options were to deal with the stuck rear brake pistons. I mentioned Jim's website.

    And I was reminded I need to get in touch with Jim to get a replacement front caliper for my EC200 enduro bike. Listed at ajpamerica.com.
    #14
  15. heffergm

    heffergm Long timer

    Joined:
    Sep 22, 2014
    Oddometer:
    2,206
    I've had the same problem on my last two GG's, a 17 and an 18. The front brake will start to act like there's air in the system (there isn't), the front wheel won't spin more than a rotation, if that. I can sometimes pump the brake a few times and it'll free up. Sometimes it will drag enough that it'll overheat and lock up entirely. When it's 'stuck' for long enough without me doing anything about it, like last event, pad wear is very uneven and severe. I had assumed the caliper was to blame with sticking pistons, but perhaps not.

    I really don't care much at this point why, I just want some basic working reliable brakes. I'd try the Brembo MC if I knew the issue was the MC, but again, not sure.

    I noted with some interest that the 2019 GG front caliper/pads are different, but who knows why.
    #15
  16. Hoss Cartright

    Hoss Cartright Been here awhile

    Joined:
    Oct 23, 2016
    Oddometer:
    623
    Location:
    Earl Park Indiana
    The new "billet" front caliper uses a different pad.
    #16
  17. Norman Foley

    Norman Foley Devotee of the Husqvarna Supporter

    Joined:
    Mar 20, 2004
    Oddometer:
    2,283
    Location:
    New York... The Finger Lakes
    Is there any variation in brake component spec, between what's supplied to different bike manufacturers? I ask because there always seemed to be a huge difference in Brembo on a KTM and an Italian Husky. I would always read online about all the problems KTM owners had with their front brakes and all their solutions. I rode Italian Huskys for many years without brake problems and very rarely a mention online of of it. I bought my first KTM product (a Husaberg) and boom.... crap front brakes! I was zip tying the front lever tight, whenever I wasn't riding. Trials market too small for this kind of thing?
    #17
  18. PMK

    PMK Been here awhile

    Joined:
    Jun 29, 2009
    Oddometer:
    378
    Location:
    SoFlo, USA
    First off, admittedly, compared to many here I am new to trials. However, the mention of KTM Brembos, and even other motorcycles and MTB sometimes see a huge variance in how the brakes feel to the foot or hand, and perform.

    For sake of argument, as has been mentioned already, flex of the caliper or master cylinder structure is something you hopefully do not have to deal with, even flexy pedals, levers, mounts or linkage.

    Additionally mentioned, not all hoses are up to the task of delivering firm brakes. Some hoses will ever so slightly expand under pressure, again hopefully this is not tne case.

    In regards to simple things that can help, and are low cost or free, these are two key items I accomplish when flushing or servicing brakes.

    #1, the fluid. From experience I learned Motul 600 RBF is great fluid, however it comes at a price. Not actual cost, but rather, this fluid MUST be flushed often, otherwise it forms crystals that will contaminate the system and render the brakes inop.

    That said, my fluid of choice is Pentosin Super Dot 4. My reason is not solely the fluids performance specs, but more importantly, so far, it always comes in a steel container. Actual cost is around $15 locally, so not to bad for a litre of fluid.

    The steel container is non pourous and does not breathe. Plastic containers I have found, while not leaking outward, seem to allow gases to pass into the fluid.

    #2, prepping the fluid. A while back, fighting soft brakes on something, probably a bicycle or my KTM, suffice to say I was getting pretty frustrated.

    With years of suspension experience, and what seems like forever ago, building my own shock vacuum bleeder, I was able to ask questions of a longtime friend about vacuum. My friend had spent many years maintaining the equipment that accomplished testing electronics for spacecraft in a vacuum environment. I was interested in learning about vacuum bleeding shocks, while he explained his equipment did not use a vacuum gauge but rather a molecule counter. Suffice to say, when he explained vacuum to the -11 power, I listened intently.

    Cutting to the chase, yes, I built a shock bleeder but this is about brakes.

    Often times, especially fluid stored in plastic bottles is contaminated with micro bubbles. These bubbles are dissolved within the fluid and are not visible. Using a Mason Jar or similar, with a tightly sealed screw on lid I now degas all the fluids used in brakes or clutches.

    The process is simple. Use an awl or ice pick, even a nail, and punch a small hole into the lid of the Mason Jar. Add an applicable amount of fluid, and this will work well for mineral clutch oils also. Use your Mighty Vac or similar brake bleeder, set to vacuum. In the kit, mine included a small suction cup to hose adapter. I use this, but without doubt other ideas might work.

    With fluid in the clear glass jar, the lid and connections to vacuum tightly sealed, apply vacuum to the fluid / jar. As you pass 22 or just higher inches of vacuum, the fluid will turn cloudy, you want to pull full vacuum of 29” or greater, then allow a few minutes to let the micro bubbles float to the top. If needed, gently swirl the jar to assist removing the bubbles.

    Slowly release the vacuum, and use the degassed fluid, avoiding adding bubbles if possible.

    My friend explained all this to me, and I, doubting his his words, since my eyes could see no bubbles, had to validate for myself.

    Semi related, when I would teach aircraft composite repair, there were times when students had bad habits mixing epoxy. They would almost whip, rather than stir the hardener in. In some instances I had them poured their mixed epoxy into a jar, pulled vacuum and they learned quickly. Void content in composites can be critical.

    Sorry for the lengthy story, but, sometimes small things, like micro bubbles, make a big difference.
    #18
    Buschog, Nobade and Bounder like this.
  19. motobene

    motobene Motoing for 46 years

    Joined:
    Mar 9, 2013
    Oddometer:
    5,326
    Location:
    Wichita Mountains SW Oklahoma
    Probably not. Other than the brief Formula debacle when filling in for AJP going under, trials brakes have tended to be all AJP/Braktec for years. Beta spec'd a white painted set of master cylinders from BrakTec for a while, which was a pretty stupid idea compared to the much more enduring standard black hard coat.

    Brembo was popular stuff decades ago, then fell out.

    The clutch and brake master cylinders have all been 9.5mm a long time and quite stable, design-wise. Even Montesa is using Euro hardware instead of Nissin, probably because the volume is too low for Nissin to justify.

    As for degassing brake fluid, hmm. Funny thing about putting any fluid under vacuum is that you can boil all sorts of constituents of solution. It's quite the show but not really necessary in systems operating at ambient pressure to higher pressure and bubbles tend not to come out of solution at those pressures. I am assuming of course the brake fluid is fresh to begin with.
    #19
  20. PMK

    PMK Been here awhile

    Joined:
    Jun 29, 2009
    Oddometer:
    378
    Location:
    SoFlo, USA
    Your call on degassing fluid. Obviously light volatiles might evaporate out. However, do not overthink this. The vacuum is short duration and quickly builds a solid column of fluid.

    Consider too, rear shocks have been vacuum bled for over 15 years. That fluid has more possibility to remove the high VI additives, but yet the trade off is worth the effort.
    #20