TR2/3/3A Question on replacing brake lines & converting to Dot 5

[GTP1960]

I am upgrading my old rubber brake & clutch hoses to goodridge ss braided lines & while I'm at it, I plan on upgrading to DOT 5 from 4.

But I'm stumped on the sequence of events.

if anyone can give me a "play-by-play" I would appreciate it.

also I have read about cleaning out the remnants of old brake fluid by blowing compressed air through the system, but I'm not sure where to insert the nozzle for this?


Any advise appreciated.

 

[Grantura_MKI]

You can put alcohol, the kind you get from a drug store to flush. You a vacuum bleeder if possible. If not flushed, you will see theseparation in the resivour.

 

[TR4nut]

I used denatured alcohol purchased from I think Home depot. Flushed the dot 4 with the alcohol then blew out the alcohol with low pressure air. Take your time you will do fine.

 

[GTP1960]

So would the process go like this?:
1) evacuate as much dot 4 in the res. As possible
2). Chase the dot 4 with denatured alcohol, using regular bleed process
3) using regular bleed process chase the alcohol with low pressure air (hairdryer thru the reservoir ?)
4) replace the old lines
5) using regular bleed process add the Dot 5

(For me: regular bleed process is; start at rear right, rear left, front right, front left, clutch)

 

[TR3driver]

Unless you plan to remove and rebuild them, I wouldn't use alcohol with the slave cylinders & calipers connected to the lines. You have to be certain to get all the alcohol out of the system.

In fact, I wouldn't even bother with using alcohol unless you pull the cylinders & calipers apart for cleaning.

 

[Brinkerhoff]

You may not gain any more by flushing with alcohol than just draining the system and pumping dot 5 through it and since its a sealed system any left over alcohol will stay inside of it and it can't possibly all "flush" out. Of course the best way is to go through the whole system and change the seals and inspect the parts , then change to dot 5. Then you know you only have dot 5 in the system.

 

[GTP1960]

In fact, I wouldn't even bother with using alcohol unless you pull the cylinders & calipers apart for cleaning.

I'm not going to clean the calipers or cylinders at this time.
i remember reading a buckeye triumph analysis of dot 5/Dot 4 compatibility that you provided awhile back.
indicated, (dot5 chasing dot3/4 directly) the two fluids will not sludge the lines, as feared.


Would you convert fluid first, then replace the old lines, then bleed out the air?
or replace the lines then convert the fluid?

Thx

 

[TR3driver]

I would remove the old lines, get as much of the old fluid out as possible, then install the new lines and bleed more or less "as usual". Since DOT 5 has a tendency to trap air, I always let it "breathe" a bit after adding to the reservoir. Continue the bleeding process until you get clean purple fluid at each cylinder.
Don't forget that a TR3 shares the reservoir between clutch and brakes, so you'll be converting the clutch as well.

IMO the order doesn't actually matter much, on a TR3. Technically, the left rear would be farthest from the MC, but your order will work fine too.

Don't worry if the pedal seems a bit soft at first. In my experience, it will usually firm up over a few days driving.

 

[bobhustead]

The instructions on the DOT5 I used said to put the DOT 5 in and go. That's what I did and bled to purple on all 5 bleeders. 3 or 4 years ago and all seems well.
Bob

 

[Geo Hahn]

...bled to purple on all 5 bleeders. 3 or 4 years ago and all seems well...

Me too - about 16 years ago on both TRs, 3 years ago on the 'new' one. No issues, great brakes.