Front brake disc conversion

Discussion in 'The whoa and the sway.' started by Droff, Dec 12, 2018.

  1. Dave GranSport'67

    Dave GranSport'67 New Member

    I have just fitted the Inline Tube conversion kit to my '67 GS 400, no problems apart from a slight rub on the inside rim to the caliper bracket, which was easily sorted by giving it a hit with the hammer. I am running original 14" rally wheels
    The kit came with new spindles & bearings, calipers & brackets, discs & backing plates, booster, m/cylinder, p/valve, hoses, bearings and the whole lot bolted straight on.
    Make sure you have the bleeder tool for the proportioning valve !
  2. cardave

    cardave Active Member

    I too am just about through with installing the Inline Tube conversion kit to my '68 GS 400 w/14" wheels ($546 on their ebay store). Overall, I am 95% happy with the quality of the parts that came. However, my kit was missing a copper caliper washer to attach the hose and a bracket bolt as well which was frustrating when you're in the mood to make some progress. Got the kit installed and realized that brake lines weren't going to line up (wish they would tell you this up front). I then bought the disc brake line kit from Inline Tube as well for another $129. Front lines fit great, rear line not so much and could not get the fitting to stop leaking. Wound up buying bulk brake line and making my own which wasn't hard.

    The other issue is that the small pre-cut brake lines that attach from the master cylinder to the proportioning valve are off about 1/4" and you can't get them to seat properly so as to avoid leaking. The brake line kit I bought from them also contained a second set of those lines and they didn't fit/seal either so clearly their mold is off. Again, ended up making my own lines for that as well. I also ended up buying the flare/file tool my by Kool Tools that sands the inside of a flare and that was a life saver in getting leaks fixed and put the finishing touch on your new flares. Along with that tool, I purchased a flat black CalVan NON chrome/aluminum flare tool as the chrome one I rented from Autozone kept allowing the tube to slip when making a flare. The NON chrome/aluminum teeth to hold the tubing are sharper since they don't have a coating on them.

    The last thing to finish up is the brake bleed. Dave GranSport '67 is spot on when he says to buy the bleeder tool that fits in the brake light switch hole of the proportioning valve to keep that valve from moving when you're bleeding the brakes. I must have bled brakes 3 times before jumping back on the internet and finding this information out. Why Inline Tube doesn't include it in their kit, nor points its out in their instructions is beyond me. What's funny, is that it's included if you just buy their master cylinder/proportioning valve kit on line. Go figure.

    Hope this information helps the next guy out. Thanks!
    MARTIN FARMER likes this.
  3. Droff

    Droff Well-Known Member

    All good information and I appreciate the input.
    It's not so much that I'm against drum brakes but I feel more comfortable with disc brakes. My wife plans on driving this car as much as I do and that's just one more thing I don't want to have to worry about.

    I have not purchased any new wheels yet, but the kit I'll be going with will most likely state 'for use with a 15" or larger wheel'. Once I get everything bolted up, I can do a test fit on the 14" wheels I've got and if they'll fit, I'll then have some tires to run through. If not, I'll start looking for some bigger wheels.
    I'm waiting until I've got things closer to an actual install before I buy the kit so maybe I can catch a discount or a sale. I had planned on buying a new brake line kit for the front as well, I ran across that hiccup in a couple other threads.

    I plan on cleaning up the frame and underside from the firewall going forward so I'm working on getting the inner fender wells out of the car with the fenders still mounted. It's a pain. I've got rust through the battery tray as well as the fender well and core support in the same area. There's more than expected rust in several other spots too.

    I have picked up a front end rebuild kit (Proforge) and a set of eBay offshore tubular control arms (with Moog replacement ball joints).
    I've started the tear down on the front, slow progress but progress, only twisted off two or three bolt heads so far.

  4. cardave

    cardave Active Member

    The saga continues.....

    Droff - Go for the disc brake upgrade. I still have a '70 Chevelle that has been in the family since new and that I learned to drive on. The 9" front drum brakes were the pits. In the early '90's I went to the local junk yard and grabbed a disc brake setup off of a '71 Skylark, installed this on the Chevelle, and have never looked back. One of the best upgrades you can do. Either I'm getting old, or people are driving faster and stop quicker than they used to back in the day as car braking systems have vastly improved.

    Proportioning Valve problems - After using the tool that fits in the brake switch hole on the PV, disconnecting the E-brake light switch, I continue to get the brake light coming on, on the dash, when stepping on the brake pedal. I have bled time several times now, pressed the button on the switch, etc. After reading a ton of information over on the Team Chevelle website, it looks like I may have one of the PV's that have a defective seal right behind the button switch. I plan on pulling the PV off here soon, disassemble it, and will report back on what I find. I guess this problem goes back years as most of these PV's are made in China. Apparently from what I'm reading and the YouTube video out there, the plastic washer that fits behind the metal end cap with the reset button on it has burrs on it that were never cleaned off. This plastic piece pushes on a rubber seal but because of the burrs, the seal leaks and fluid can come out the button hole, which in turn would cause a pressure loss and make the light come on. This all makes sense to me. I'm just hoping the seal isn't destroyed yet and I can just file down the burrs. I'll report back on my findings.

  5. DasRottweiler

    DasRottweiler -BuickAddict-

    I will be doing the same conversion in the spring. All drum 70 Skylark, looking for more whoa power at the end of the track.
    I have all the parts required, stock replacements from another Skylark. I did buy 2 new disc spindles from Ground Up and will be sourcing the wearable items, ie: pads , rotors from Summit. I purchased a disc master cylinder from Mark Moleary last year in preparation for upgrade and I will be ordering a new prop valve from Inline Tube #PR102 per Brian Trick's recommendation from another thread.
    Other thread:
    I plan on using skinnies up front on 3.5" rims while at the track to replace the 235/60-15s I run on the street. I also have a Hurst Roll Control installed to lock front brakes in the burnout box which won't hold with the drums, perhaps another issue...
    I would like to add to the plumbing an adjustable valve to control front brake pressure. My thoughts: Turn pressure down wih the skinnies to prevent locking up the front tire when hitting the brakes at end of track and turning it back up when the 60's go back on for street use.
    I will be using the prop valve mentioned above #PR102 and possibly this inline with the line lock to control front brake pressure:
    Seems most folks use this 1 inlet/1 outlet valve inline in the rear brakeline to control rear drum brake lockup after a disc install/ upgrade to front brakes. Is it unnecessary for me as I intend to use it?
    Input appreciated.....Jim/Rott
    Last edited: Jan 12, 2019
  6. I did the right stuff 14" wheel conversion on my '69 skylark a few months ago. They turn down Camaro rotors from 11" to 10.5" and use stock calipers from an older Chevy, I think a Celebrity. Pretty easy install, but I needed to replace the brake lines on my convertible with their "Conversion" brake lines, as the routing up the firewall is different. Very happy with the increased stopping power, and the install was very clean. Not original looking but nice. Since I converted from non-power to power, I also have to add the correct vacuum hose nipple on the intake, and the correct hose as well. When you buy these kits, expect the directions to have lots of holes in the install that you will have to research.
  7. lemmy-67

    lemmy-67 Platinum Level Contributor

    My '67 has a custom conversion to front disc with 12" rotors. Works great with the existing master cylinder and prop. valve.

    The rotors & hubs are stock Bendix from a '99-04 Jeep Grand Cherokee.

    The 2-piston calipers are from the same year Chevy Avalanche/Caddy Escalade.

    MP Brakes in North Carolina fabricated the brackets for my spindles (from 1968 4-piston setup), and sourced all of the parts.

    Only catch, stock Buick 15" rally wheels won't clear the calipers. Even the rallys with the bulge from the 4-piston system won't fit.
  8. Droff

    Droff Well-Known Member

    I went with a Right Stuff set up, everything looks like brake parts. Go figure.
    Slowly working towards getting to the point of install just too many things to fix/repair on the way.
  9. Droff

    Droff Well-Known Member

    Concerning the drums I've taken off .....
    I have the all of the front drum brakes with upper/lower control arms in a neat pile (usually in the way). I do not plan on putting these back on the car.
    Is there a market for original GS brake parts like these or just giving it to a scrapper as the typically resolution? I don't have room to keep everything laying around.
  10. DasRottweiler

    DasRottweiler -BuickAddict-

    Control Arms , in good condition are saveable. Drum spindles and drums , probably not so much, but someone may have a use for them. For Sale forum or Pay it Forward forum ......Jim
  11. I'm fairly certain there is a difference between power and manual disc brake master cylinders. That's why the 70 olds w30 has a different part number for manual disc brakes versus a power disc brake application. I researched this in-depth before I bought my manual disc brake parts. The manual disc brake master has a smaller bore
  12. BrianTrick

    BrianTrick Brian Trick

    The difference is between drum/drum and disc/drum.
    The drum/drum has a 1 1/4” bore.
    The disc/drum has a 1 1/8” bore.
    The manual brake masters have a groove machined into the back,to help retain the pushrod cup,but one without the groove will work.
  13. cardave

    cardave Active Member

    Update on my project. I last left everyone off with having installed the Inline Tubing disc brake kit and a brake light on the dash that wouldn't go off. After installing Russell speed bleeders on the rear, bleeding the brakes more times than I could count, still can't get rid of the light on the dash. I called Inlines support desk and was advised to bleed both front brakes at the same time as I had done this to the rear to eliminate any chance of air, but bled the fronts individually. Inline thought that bleeding the both fronts at the same time would center the little piston inside the combination valve. Did all that, light still on.

    At this point, my reading led me to believe the combination valve was defective. Bought a new aluminum one, installed that, re-bled system, and after 22 miles of driving so far no more light on the dash! Brakes have a totally different feel to them.

    Now I need to find out why I get a scraping/swishing noise from the front wheels upon braking, that gets louder the farther down you press the pedal. I have 14" Buick sport wheels that are not original, but have a manufacturing date of 1982 and were made in Canada. The Inline Tube kit I bought was specifically for 14" wheels. This weekends project will be to pull the wheels off and check to see if the caliper or the caliper bracket is rubbing the wheel.

    For being a "bolt on" kit, I've had my fair share of frustrations with Inline Tubing.
    69GS430/TKX and MARTIN FARMER like this.

    MARTIN FARMER Well-Known Member

    The bracket.on.Inline.says
    Thanks, Mart

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