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Triumph TR6 - Brake bleed w vacuum
|I thought it was time to start new thread re the DOT 5 issue. I am using DOT 5. Interestingly point that my .5 is not purple anymore..Even in the sealed bottle. Coming out of the bleed process is more a golden brown. I started with literally!! all new brake system and I know there is NO mix of another fluid (DOT4). Rick O you are using the Mityvac unit? So here is my question. With the Mityvac hooked up to bleed nipple with hose, I can pump up to 25 in (lbs?) or 60 on the other scale and maintain the vacuuum while bleeding.. how do I know if the tiny bubbles are coming out of the system or are they bubbles leaking past the threads of the bleed nipple? Fluid is going down in the MC reservoir and I am keeping it toped up. Any thoughts guys? Should I do one final pump (slowly) of the brake peddle? Oh ya, starting at passanger rear.|
|WIth almost complete certainty, the bubbles you see are what you thought--bleeder screw thread leaks. I guess you could teflon tape them, but I wouldn't bother. I had the same bubbling at all four corners, which I ignored. THe bubbles were tiny, like a good champagne. The only thing you need to look for is the new fluid being purged because it's almost impossible to leave air in the system when vacuum dragging. When you are done, you will find that your pedal resistance is solid with no sponginess; that's the final test! I think 25# is a bit high, so you should open the bleeder a small amount. If you are lucky, you won't shift the PDWA piston like I did. Resetting it wasn't difficult though.|
Yes, I used the MityVac unit with great ease. I can attest that purple DOT5 will fade over time. If unsure, just mix yours with some glycol; the separation will be obvious.
|Hi Rick O|
I have done 3 corners so far and did the final purge using the old fashion method....3 to 4 slow pumps of the brake pedal. No bubbles. There where no champagne bubbles with the brake pedal. I already had teflon tape on the bleed screws and I guess with the continuous tighten / loosen the tape might have ripped ...as you said tiny little champagne bubbles. Even with the bubbles the reservoir was going down so I obviously was drawing fluid through. The vacuum method unfortunately does not give you the definitive answer as to what you DO NOT want to see. The final pump of the brake pedal does say NO BUBBLES. I will finish F.L. corner with this double method.As a plus comment to the Mityvac, it is a good tool to introduce fluid to an empty brake or clutch system and also to empty a reservoir (as u probably did). Yes, DOT 5 looses its purple colour..so one might ask why is it purple to start of with? Yes I expect to re-center PDWvA....agreed,no big deal. This next comment I am sure will raise a few eye browns. DOT5 can be recycled (DO NOT do the following with DOT3 or 4). After filling up the little plastic bottle of the Mityvac (many times), I empty it into another empty bottle of DOT5 through a funnel lined with a coffee filter (not a paint filter...to course). This can now be reused.
I am going to submit a second entry on the subject of DOT5 so read on.
Thanks Rick O
|Now you tell me that DOT5 can be recycled! I already tossed a half-quart or so. Guess its a function of how long you go between system bleeds, but I don't know whether I'd use recycled silicone. TRF has DOT5 quarts on sale for $16 now. Rick O.|
|The recycle thing is me being cheap. It is very expensive up here. I have not convinced myself that I am doing the right thing. The coffee filter does work though. Being that .5 is not hydroscopic air contamination will not affect it. ( I am trying to convince myself here).|
It is amazing what I have been reading on the WEB about .5 and .4. The general opinion is 2:1, do not use silicone. About the only time I see use it is in antiques that are driven a lot less than our other cars and ones that might sit for long periods of time. I have had one person say to me that .5 and .4 are 100% compatable. He refers to the DOT spec. for brake fluids (FMVss116) that they must be compatable with one another. I have read a promotional/sales blurb (on an antique british car WEB page) that says to go from .4 to .5 simply drain the brake system and refill it up with .5. I am under the impression that they do not mix and that doing this change over from 4 to 5 requires that all seals and hoses should be replaced. Simply put... seals that have been soaking in .4 then system converted to .5 the seals will deteriorate very quickly to the point of leaks and brake failure. I have put an e-mail out to a manufacturer of both fluids and have asked what colour is .5 and has it always been that colour. Also what is entailed in converting a brake or clutch hydraulic system from .4 to .5....should all brake rubber components be renewed? I will post the response...if I get one.
remove the bleeder screw. and carfully put heavy bearing grease on the threads of the bleeders, this prevents sucking air. It also prevents corrosion later.
As Rick O would say "now you tell me".I am done. Thanks for the tip..sounds logical to me.
|For 11 years, I have used purple silicone brake/clutch fluid in my TR3A and whenever I bleed or drain some, it is black. I let it sit a few days and syphon (pour) off the clear clean purple top layer of fluid and re-use it.|
Never had a problem.
Don Elliott, Original Owner, 1958 TR3A
(Down here for the golf and the warmth - till it's time to get the 3A back on the road.)
|Not on the fluid topic but with bleeding techniques I just purchased the Easybleeder screws. My car has sat for two years for a minor upgrade of parts and went to use them on an empty system. I am impressed indeed. They work very smartly.|
|Mistake on the name of the above bleeding screws. I want to give correct name for the company . It is Speed Bleeders.|
The DOT 5 issue continues.....I sent an e-mail to a manufacturer of .5. Company is Russell Performance (an Edelbrock company). I asked the question re colour of .5 No answer. I asked how do u tell if you have a mix of .4 and .5 in a system.. reply "No clue how you could test to see what brake fluid you have.The best thing to do is to flush all the fluid out and start all over". No mention of what to flush system with. Also asked what is involved in changing a system from .4 to .5...do seals need to be replaced? reply..."All you need to do is flush the brake system". Now the interesting point. On there WEB page at the very bottom of the blurb on their .5 fluid is in small print the following..."(Do Not Mix with Non-DOT 5)". It must have been 4:59 PM on a Friday when he replied.
Don E. Try the coffee filter thing after u have let it sit...you might be surprised how much more u get out.
P.S. Speed Bleeders are from Russell Performance.
|Based on my recent experience, the easiest way to confirm DOT5 or non-DOT5 is to mix a little of the "unknown" fluid with some "known" DOT5 and watch for phase separation. If you have separation, then the "unknown" must be non-DOT5 (glycol).|
Regarding Don's comment that his fluid always turns black, I suspect that the black is coming from his seals. I don'lt know if this is normal for a DOT5 system (it is normal for a glycol system).
|Reply to Rick Crawford |
I filtered it with a coffee filter - also with a paper towel - and all that - and it always came back to purple. I'm in no hurry ! I just let it sit in a clean glass jar and I can see when I need to pour (syphon) the purple fluid off.
In the meantime, I refill the master cylinder with new purple fluid which I always bought from Roadster Factory in a quart plastic bottle - except for one time when I needed some in a hurry, and bought it (also purple) from a local Harley Davidson shop.
Don Elliott, 1958 TR3A
This thread was discussed between 20/02/2002 and 05/03/2002
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