Results 1 to 10 of 10

Thread: Replacing Rear Brake Lines is ABS Module Bleeding Necessary?

  1. #1
    Join Date
    Dec 2011
    Posts
    15

    Replacing Rear Brake Lines is ABS Module Bleeding Necessary?

    1994 SC auto with ABS and Traction Control

    Need to replace the rear metal brake lines due to failure caused by corrosion. After 24 years and 176,000 miles I can't complain, but don't look forward to doing this job for fear of having to do the ABS Module bleeding.

    I've made certain all the lines will come loose, but before I disconnect completely want to know if bleeding the ABS module will be necessary. After reading various links about bleeding the Mark IV system I got the impression the module is bypassed during normal operation and all the internal valves are closed. I could have misread the threads and my understanding in error. If I'm correct, I'm thinking the ABS module bleeding might not be needed.

    The master cylinder has not run dry yet.

    For reference I'm replacing the lines starting at the bottom of the front drivers side tire at the big 22mm union.

    1. Will it be necessary to bleed the ABS module using the required "special" tool if replacing these lines?

    2. Any ideas on where to rent a special tool to do the ABS bleed process?

    3. Any suggestions on how to plug the fitting, so air isn't introduced? If I knew the fitting type/size at the connector, plugs could be purchased/fabricated ahead of time and be installed immediately after disconnecting the lines.

    4. Does anyone know the fitting sizes and end details (double flair or bubble flair) so I can purchase tubing ahead of time? Never had any luck double flaring brake tubing, so will buy the premade type.

    Thanks in advance for your help.

  2. #2
    Join Date
    May 2002
    Location
    Dallas, TX
    Posts
    5,715
    Here's what I would do.. You shouldn't have that much air in there from just replacing the lines. Also, since the ABS is separate part of the braking system, unlike our Teves 2 on my car, I would do a standard bleed for the rear lines. As long as you are able to get fluid to flow out the bleed valve, you should be good. Try your brakes, if they feel solid, go with it.

    Later on, test the ABS on a slick surface and see if there are any issues.

    As for a plug for the lines, I don't know the fitting size, but it might be posted out here. The brake fittings are not metric, nor SAE, but strangely enough, NPT So look in the "NPT" boxes, at the hardware store, for a match.

  3. #3
    Join Date
    Dec 2011
    Posts
    15
    Thanks for the quick reply!

    Brakes were very firm prior to the line failing and the master cylinder is still more than 3/4 full. As the vehicle sat for several days after the brakes went to the floor, there is no evidence it continues to flow via gravity.

    I still want to minimize the possibility of air getting into the system, so looking for thread/fitting to create a plug as noted in post 1. Just trying to minimize risk.

    Here's a photo of the fittings in question:

    Name:  Brake fittings.jpg
Views: 121
Size:  166.0 KB


    Has anyone had success making their own ISO Bubble ends? If so, what tool did you use?
    Last edited by L3130; 02-13-2018 at 08:31 PM.

  4. #4
    Join Date
    Apr 2002
    Location
    Madison, Ohio
    Posts
    17,594
    You can make your own bubble flares. You'll need the proper tool which you can get just about anywhere, you might even be able to rent it from a parts store. I use the more expensive nickel copper brake lines to make any new lines because they are much easier to form and corrosion resistant.

    As long as you don't let air get into the ABS from the top you shouldn't need to bleed it. I suggest making or buying caps for the lines to minimize leakage during repair time, and top up the reservoir while working. You can also seal the reservoir to minimize siphoning. The stock cap is vented, so put something on there to seal it during your work.

    When you are done, bleed the system normally. If you end up with a full pedal and no air in the system then you can assume you were successful. If not, I have the tool to power bleed the system and will rent it to you for $25.
    Quote Originally Posted by Miller View Post
    Ya thats why i tape mine down. People think its bc i dont have a moonroof seal (which is true) but its really to keep my roof from ripping off .
    Email me here.

  5. #5
    Join Date
    Dec 2011
    Posts
    15
    Thanks for the info XR7 Dave.

    Based on measurement using a dial caliper and thread gauge, I believe the thread size to be M10x1.00 and M12x1.00. Plan is to procure something to plug the fittings first and then proceed with the repair. Thanks for sharing your experience with the nickel copper lines. In the far past I didn't have much luck making double flares, but realize newer material are easier to work with. (I realize double flare is different than ISO Bubble)

    Thanks for offering the rental! I'll let you know if I need it.

    Appreciate all the help.


    Are there any tricks for snaking the line from drivers side to passenger rear?

  6. #6
    Join Date
    Apr 2002
    Location
    Greenville, IN
    Posts
    4,415
    The correct ISO Bubble flare tool would be ideal, but you can (carefully) do a bubble flare with a double flare tool. It's easy to mess up though (recut, try again).

    Just make sure you keep the master cylinder full!
    Matt Haub
    Shootouts: '09 SS 1st | '10 Mod1 2nd | '11 Bracket 3rd | '12 Bracket 1st | 2013 | '14 Bracket 3rd | 2015 | '16 Bracket 1st & Mod2 2nd | 2017 |
    Black '89 5spd - 281K miles, MPx, E85, Alky-Inj RWHP: ? RWTQ: ? Best 1/4mi:12.521, MPH:107.23mph
    35th Anniversary Auto 46k miles | Red '93 Auto 186k miles
    My Garage

  7. #7
    Join Date
    Dec 2011
    Posts
    15
    Just an update...

    First off the two fittings at the front drivers side wheel (reference photo in earlier post) are M10x1.00 and M12x1.00 utilizing 3/16" tubing.

    Rented a flaring tool (from AZ) and practiced on some preformed tubing purchased to make the plugs and confirm the thread size.

    Flaring process:
    1. Cut and squared up the tubing end
    2. Chamfered using small fixture on a circular sander (Common: 6x48 belt sander 9" 200 grit circular sander combo) to make certain chamfer was consistent around the perimeter. Also debured the ID
    3. Placed tubing in fixture at appropriate height
    4. Positioned die and screw fixture and tried to align (Die was lubed)
    5. Tightened screw fixture, but didn't over tightened

    In other words I tried to be very careful with prep/setup before attempting the flares knowing it was very important for success.

    Results:
    5 Trials: 1 looked good but not factory quality, 1 useable and 3 that were bent/off center. Tubing material was the coated steel type, not Nickel Copper.

    Observations:
    The rental tool was brand new (still had plastic shrink wrap), but was for a flare and double flare, not ISO bubble. This was a bit frustrating as I talked to the parts person that I needed an ISO bubble and he said to just do the 1st step of the 2-step double flare operation. I'd feel better if it was specifically designed for ISO bubble. Compared to the factory formed end and the ones from this tool, they are not the same. Useable, but not the same.

    The screw fixture doesn't look to be aligned with the tubing. It tilts a few degrees and this seems to be what makes it difficult to make good bubble flares. This could be fixed by filing/machining the surface of the screw fixture the holds against the tube vise. The surface is as-cast and has draft. An additional machining operation during tool production would go a long way in improving the success rate. If the tool was mine, I'd modify. Since it doesn't make a true ISO bubble I'll take back and see if they have one specifically for the ISO Bubble and hope it has better alignment.

    Line plugs were made by using an empty 22 shells. Filled shell with solder, heated and then plunged the tube into case/solder and let it solidify. They worked great, sealing for several days before I could work on it again. Prep ID and OD of tubing and shell casing along with using flux. First attempt to plug line was to run a sheet metal screw into the tube, but the fluid still dripped. Note - Store didn't have plugs. They might be available, but they didn't stock any.

    I'd like to become more proficient with the flaring tool to make 1 or 2 piece lines, but not thinking this is likely given my current inability to make good looking flares. The alternative is to buy a number of premade tubes and splice using unions. If flaring my own ends planed on using Nickel Cooper and would use coated steel if going prefabbed pieces.


    QUESTION

    For those who have formed flares on both steel (or coated steel) and Nickel Cooper, what was your success rate between the two?


    I'm just trying to predict improvement using Nickel Cooper before shelling out the $'s for a spool.
    Last edited by L3130; 03-04-2018 at 07:25 PM.

  8. #8
    Join Date
    Apr 2002
    Location
    Greenville, IN
    Posts
    4,415
    I don't think the ISO bubble flare tools are readily available at auto parts stores, nor tool stores - you can order them off Amazon or eBay though.

    If you're not getting good flares with the tool you have, a bubble flare definitely won't work out with that tool. Again though, you COULD use that tool you rented (assuming it's listed as a single/double flare tool) to do ISO bubbles. Basically, you'll do a normal single flare, then do half of a double flare, stopping when it looks like a bubble flare. If interested, look up some youtube videos. I used this method this past summer and easily got 3 or 4 leak-free brake line connections (after I got them tight enough).
    Matt Haub
    Shootouts: '09 SS 1st | '10 Mod1 2nd | '11 Bracket 3rd | '12 Bracket 1st | 2013 | '14 Bracket 3rd | 2015 | '16 Bracket 1st & Mod2 2nd | 2017 |
    Black '89 5spd - 281K miles, MPx, E85, Alky-Inj RWHP: ? RWTQ: ? Best 1/4mi:12.521, MPH:107.23mph
    35th Anniversary Auto 46k miles | Red '93 Auto 186k miles
    My Garage

  9. #9
    Join Date
    Dec 2011
    Posts
    15
    First off thanks for everyone's input and suggestions.

    Ended up using various lengths of premade Nickle Copper (NiCopp) lines. I wasn't able to rent a flare tool specific for bubble flares and wasn't happy with the double flare pretending to be a bubble flare when using steel lines. Perhaps it would have worked with the NiCopp lines, but I needed to get the job done and didn't want to continue practicing making ends.

    The NiCopp lines was very easy to bend. Used a few deep sockets to help form some of the tighter bends. This material is expensive, but well worth the money in reduced fabrication time and it can be reworked if necessary.

    No surprises when bleeding the lines and a firm pedal was easily achieved.

    It took two sections of tubing to make the drivers side rear and three pieces for the left rear. The best I could measure the original lines put them at 116" and 150" long. Must also mention the tubing was available with 10mm ends, so adapters were needed to get to 12mm.

    No leaks and brakes work. I'll call it a success and thanks again for everyone's help and tool rental offer.

  10. #10
    Join Date
    Apr 2002
    Location
    Christiansburg, VA
    Posts
    148
    Looks like I'm in the same situation as of today. I appreciate you sharing your repair followup. What lengths, unions, and fittings did you buy?

    Thanks,
    94 SC 5sp.
    Mods: ESM SC Top, IC Fan, dual 2.5" exhaust, mac intake, 300w pioneer sub, Cobra cowl hood, 97 front lights.

Similar Threads

  1. Replies: 3
    Last Post: 07-13-2008, 05:00 PM
  2. Rear Brake line
    By Dragon in forum Technical Forum
    Replies: 5
    Last Post: 11-29-2005, 07:03 PM
  3. rear brake lines
    By thebigslide in forum Non Technical Forum
    Replies: 0
    Last Post: 10-25-2004, 10:29 PM
  4. Rear Brake lines Needed ASAP
    By Miller1995 in forum Want to Buy
    Replies: 3
    Last Post: 09-19-2004, 11:27 PM
  5. Two-wire sensor on rear brake line?
    By Parker Dean in forum Technical Forum
    Replies: 3
    Last Post: 01-23-2003, 12:00 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
  •