As you know from a prior post, I had brake problems that are probably cured with backing out the tube with the guts of the master cylinder so the bleed screw worked. I've also converted to DOT 5 and cleaned out the whole system prior too.
I've emptied the last of a 12 oz. can of DOT 5 into the resevoir and have no air coming out the bleed screw yet not even a hint of a hard brake pedal. I've resnugged all the fittings. Blocked the caliper pistons in with a piece of wood and have the caliper hanging from its bolt in the approved manner.
I've tried the bleeding methodology in the manual of attaching a tube, cracking the bleed screw and pumping the pedal. Also the old method of pumping up the pedal (I wish) with the screw tightened and while gently holding down the pedal releasing the bleed screw and retightening before releasing the pedal. Note: the DOT 5 says to use this manner, but push down on the pedal and releasing slowly, which of course I have tried as well. Of course, I've kept the resevoir at least half full throughout the maneauvers above.
In the past having no pedal while bleeding was common until magically I started to get pedal and was able to successfully get a hard pedal. The magic is gone. Got any ideas or comments?
PS: I have searched on "bleeding brakes" and find nothing that will help or haven't been tried. Curious how the search seemed to pull up many brake problems with the same breed of Triumph.
Everything has to be downhill from where you are trying to bleed the air out. If you started with an empty line the large bubbles might not go through the small reservior bleed hole in the master easily. Either pressure on the reservior or vacuum at the caliper is the usual way. Some people keep an extra reservior cap with a Schraeder valve bolted through the top to use an air pump to pressurize it (very low 1-2 PSI). Another way is to use a syringe of brake fluid on a drilled bleeder screw (drilled through the end so it can be tightened and still pass fluid) and push the fluid back up the line/master to the reservior. Once you have the line filled you can bleed as normal.
Re: Bleeding brakes - can't get hard - T140V#131868 01/01/0810:38 pm01/01/0810:38 pm
My bleeding apparatus is the L-shaped rubber slip over the bleed nut thingy with a clear hose leading into a cup. Inside the cup the line extends down another two inches. On the other side is a vacuum port that I can use a hand actuated vacuum pump. Think that would work better than what I had described previously?
I don't have a spare cap to make the Schraeder valve cap. Your syringe Idea is unclear to me. Pushing from the topside seems less problematic than trying to push it out the top of the resevoir.
Do you think my issue is air in the system? I have zero pedal and no air being bled out in the standard manner. I am able to bleed the system. Even with some air, I should get some pedal, albeit spongy or minimal. Right?
Re: Bleeding brakes - can't get hard - T140V#131869 01/02/081:04 am01/02/081:04 am
The problem with a vacuum bleeder on the caliper screw is that air passes down along the threads and into the vacuum line so you cannot see if any air is coming from the brake line. You will never be able to pull air bubbles down from a high spot in the line. It might be a problem positioning the master with the line end down enough. When you bleed in the traditional way it is difficult to fill the line since compressing the master, opening/closing the caliper bleed screw and releasing the master generates very little vacuum in the line to pull fluid in through the master feed hole. So it is best to start by another method. Pushing the fluid down from the reservior has the problem that the air wants to travel up and fluid can push past bubbles in the line. Because of the afore mentioned problem with air (and fluid) getting past the threads of the bleed screw, buy another and drill it straight through. Be sure to clean off any burrs around the hole or else the stock screw will not seal on the taper. Fill a syringe with brake fluid and attach it to the drilled bleed screw that is tightened in the caliper. Push the fluid up through the line and master to the reservior. It will carry the air up and out of the line. You may need more than one syringe full. After you filled the line, replace the bleed screw with the original and bleed by vacuum or pumping the pedal. Also, if you let the caliper pistons extend (but obviously not out) then push them back in with a lever you will get more air out than by pumping. If you have enough air in the line you would not feel any resistance compared with the pedal return spring. Too small of a volume change.
Re: Bleeding brakes - can't get hard - T140V#131870 01/02/083:21 am01/02/083:21 am
I cannot find it for the life of me right now, but I bought a bleeder on eBay... called easy bleeder, or E-Z, or EZ; well you get the idea. Replaces the bleed screw; has a one way valve, and thread sealant to keep air out while cracked to allow fluid motion. You install this gizmo, loosen 1/2 turn and simply pump the lever or pedal. Used the same one on both front and rear of my '76 T140... one man bleeding, first time from empty, both ends. I recommend!
Re: Bleeding brakes - can't get hard - T140V#131871 01/02/085:07 pm01/02/085:07 pm
Yes, I have seen those. I do not remember how they seal the thread. Obviously it has to be loosened to bleed otherwise fluid will come out every time you push on the master. Still, you need to overcome the sealing pressure of the check valve. If there is a lot of air in the line the master will not develop enough pressure to lift the check ball.
Re: Bleeding brakes - can't get hard - T140V#131872 01/02/089:41 pm01/02/089:41 pm
This thread caught my attention because I'm just about to disconnect the brake line on a T140.
I've successfully bled car brakes a number of times with nothing more than a piece of hose and a coffee can (and a helping foot to pump the pedal). Is there something different about this brake that it requires special equipment to bleed?
As I'm changing my bleed nipples for stainless I'm going to use the old ones so I can fill bottom up - makes perfect sense and wastes less fluid. Now all I've got to do is buy a BIG syringe without attracting attention...
Re: Bleeding brakes - can't get hard - T140V#131876 01/03/0810:21 pm01/03/0810:21 pm
Looks like Blapper and I will be looking for a similar syringe. I have the caliper off the front, which I replaced with the racing Lockheed some time ago, thus a nipple to bore out.
I found the EZ Bleeder Trumpetloon refered too. Goodridge Speed Bleeder. They come as a set of two and hopefully I measured correctly, size 10MM X 1.00 costing $20 delivered. (I found a number of other one-way bleeder devices available as well.) I plan to bleed out all the DOT 3 from the front caliper and replace it with DOT 5 and this device will make it easier as the nipple is topside between rotor and spokes. A most unhandy location.
Latest on my rear brake bleeding: After letting it set overnight I had a spongy half pedal. Bled it some more, but damn near no pedal after the first push. Let it set a few minutes and the near half pedal was back and bled some more. Other than an inital single bubble, no further air bubbles coming out. Don't know if that bubble was between nipple and rubber L-shaped bleeder to start with.
Re: Bleeding brakes - can't get hard - T140V#131877 01/04/0812:55 am01/04/0812:55 am
If you rebuild with DOT 5 after only dropping all the DOT 3 out, you are wasting all the time and fluid you've used so far. You MUST take it all apart and at least wipe it out thoroughly (including the lines). The reaction between the two fluids will just make a stodge in there otherwise. Read the DOT 5 info on the www.gabma.us tech bulletins page, don't take my word for it.
Re: Bleeding brakes - can't get hard - T140V#131879 01/05/089:25 pm01/05/089:25 pm
Blapper; read some of the replies I got from my original post where we presumably diagnosed my problem with the master cylinder. Several guys responded saying that they simply topped off and bled the the system without removing the the DOT 3 and have had no ill effects!
JubeePrince; my email address is email@example.com and yes I am interested in the Lockheed manual. Here's why:
I found a syringe, one used for injecting marinade into turkeys, etc. $10 at Bed Bath and Beyond, steel sleeve over plastic with two solid needles. Holds 1.5 oz of fluid. Drilled out a nipple to just under the size of the needle, which too is smaller than the nipple bleed hole. Squared off the pointed needle nose and have pushed 6 oz. of DOT 5 out the resevoir. Takes some serious pushing to get the fluid all the way to the top and some escapes out the nipple.
I did get some very, very tiny bubbles up my clear hose. I saw no bubbles on the last two syringes full and then bled as normal with again no bubbles. I still get a reasonably firm first one-half pedal and none after that. This is when bleeding the system. Pump the heck out of it and I get just a little pedal, but still move a reasonable amount of fluid through the hose. It just won't pump up to a hard pedal then purge, redo, purge again. A function of DOT 5? A half pedal is better than no pedal! I lose the half-pedal when I bleed, but if I don't bleed I would still have the half-pedal. Yes, I'm getting frustrated with this. I still need to put something the same size as the rotor between the pads to affirm that the calipers retract after braking.
As for measuring for the Goodridge Speed Bleeder, I used my thread gauges for the 1.0 part and I measured the from outer thread edge to opposite edge with caliper arriving at 10MM. This corresponds with the sizes offered by Goodridge. The bleeder screw is original equipment off my '78 T140V. Hopefully I did it correctly.
Re: Bleeding brakes - can't get hard - T140V#131880 01/05/089:31 pm01/05/089:31 pm
Geryrace, is the caliper mounted on the bike or off? Is the line and bleed screw on the same end or opposite? I am not sure if these calipers are the same configuration as the ones used on the '73-'75 models. Is the split line in the centre of the disc or offset? The reason is the cross hole location. You may have to tilt the caliper so the internal drillings form an continuous uphill line toward the bleed screw. Otherwise you will have air trapped someplace.
Re: Bleeding brakes - can't get hard - T140V#131882 01/06/0812:49 am01/06/0812:49 am
Originally posted by Blapper: If you rebuild with DOT 5 after only dropping all the DOT 3 out, you are wasting all the time and fluid you've used so far.
Not necessarily. In Gery's other thread, I mentioned that, not knowing any better, simply "dropping all the DOT 3 out" and refilling with DOT5 was all I did on one of my T160's. That was 25-odd years ago, I still have the bike, most of the DOT5 still in it is original, and I've never had a problem with that bike's brakes.
Also, what I've since remembered is that any DOT5 you buy today almost certainly meets one or other of the SAE J1703 specs. (it'll say on the container). I was specifically advised by one of the DOT5 tech. guys at Fuchs Lubricants (the maker of my 'Silkolene DOT5 Brake and Clutch Fluid') that the SAE J1703 specs. specifically include the ability to intermix with glycol-based fluids without problems.
That said, then the bumf on the container does specifically advise stripping and cleaning with methylated spirit the parts of any system previously used with glycol-based fluid, before filling with DOT5. :rolleyes:
Hth (probably not :rolleyes: ).
Re: Bleeding brakes - can't get hard - T140V#131883 01/06/089:18 am01/06/089:18 am
It is clear that there is contradictory evidence in this matter, but in that situation, there are a couple of things you can do; take the cautious route (it is brakes we are talking about), or the easiest route. What tends to happen on this forum is that people keep asking the same question until they get an answer that coincides with what they want to hear or can be bothered to do (your answer in this case - I found no evidence of the 'several' quoted by Geryrace).
But if you ever take your calipers apart for overhaul, it would be very interesting to see whether the stodge (or resultant rust even in 25 odd years) that is said to be formed is actually present, particulary because you made no effort to remove all evidence of the DOT 3. As you haven't done this, it could be there, just not in a place which is causing you a problem (yet?).
Personally, it gives me a good feeling to know that I have considered all avenues and done the best - seldom easiest - job I can. In this case, I find nothing to lose except an hours work, so it is a no brainer.
Re: Bleeding brakes - can't get hard - T140V#131884 01/06/084:25 pm01/06/084:25 pm
Blapper: I hear you about brakes. Since the front are easy to deal with, I'll not risk it and just be a good boy and bleed them annually with DOT 3 until some reason occurs for me to tear them down.
DMadigan: I thought my '73 had drums on the back? Anyway for my '78 it calls for drifting out the axle so the caliper hangs vertically and the bleed screw is on top. I have it hanging in the aforementioned manner.
Stuart: My DOT 5 is made by North American Oil Company, Kennewaw, GA and says nothing about not mixing it with other fluids. It does say: "Contamination with with dirt, water, petroleum products or other materials may result in brake failure or costly repairs." (Maybe that is their wiggle room per their legal counsel.) And that it conforms to Federal Mortor Vehicle Safety Standard 116. What ever that is.
Re: Bleeding brakes - can't get hard - T140V#131885 01/06/084:58 pm01/06/084:58 pm
Maybe the soft brake problem is the 30plus year old brake hoses. Most flexible hoses swell up like balloons under pressure. Have someone pump a brake lever while you hold the flex line and you will be very surprised at the bulging. You may have to get steel flex lines to get the solid lever/pedal feel.
Re: Bleeding brakes - can't get hard - T140V#131886 01/06/086:08 pm01/06/086:08 pm
The caliper design, whether used on the front or rear, was the same. The bridge over the disk was part of the mounting side. The secondary (back side) piston housing has two small wings extending beyond the bolts that hold the pieces together. These wings are where the cross drilling is located. You need to tilt the caliper sideways so the bleed screw is the highest point. If you can get the pistons to move using the pedal, extend them out equally with about a 0.2" gap. Shake the caliper to move any air up the line to the master then put a lever between the pads and push the pistons in. See if you get any bubbles in the reservior line. It is difficult to move air down the line. Air at the master has to come out through the small hole (~0.025") and to do this the fluid has to return to the reservior when the pedal is at rest (which is why the hole has to be open in the rest position). Caliper pistons only retract a small amount due to the seals. Pushing the pistons in will help purge the air.
Re: Bleeding brakes - can't get hard - T140V#131887 01/09/088:39 pm01/09/088:39 pm
Success! Took it for a short ride (28 degrees) and rear brake works fine. It is so good to have it back after all these years of my fiddling with it and "professionals" ignorant of how to test, diagnose and cure the problems.
As a recap and recommendation to those that follow. The fundamental problem was in the proper adjustment of the master cylinder such that it would allow it to bleed back when the pedal was released so the brake pads would retract. In my case I had to back it out two turns before air blown in the exit side came out the bleed hole under the saddle.
Next problem was getting air out of the system and the use of a drilled out bleed nipple and a syringe worked best. Removing the caliper from the hanger so that it was was only attached by the hose and allowing it to be manipulated around to get the air out of the cupped caliper pistons was necessary. Further, being able to place the caliper on a suitably high box and pushing fluid (DOT 5) backwards through the drilled out bleed screw while standing over it and using body weight to push the plunger was a lot easier than otherwise attempts.
Lastly, one of the respondents said use a clear vinyl tube from reservoir to master cylinder was a stroke of genius because now I could see if any bubbles of air was rising to the resevoir from the reverse bleeding method.
Thank you so much guys for sticking with me through this. My next project is dealing with the Prince of Darkness headlight switch.