leak form rebuilt slave

[turbocamino]

 I can see it running out from around the new seal   why me!...i hate brake fluid....i cleaned everything very well.  where the large seal wraps around the cup and into the grove,can i put some silicone there? thanks.

[RichBaker]

You could, but it wouldn't help the leak any.... your slave cyl is probably out of spec, to big, to seal. You probably need a new one....

[SlowOldGuy]

If you just cleaned/replaced the outer seal, then you didn't address the real problem.  The inner bore is probably corroded and teh inner seal has hardened or been damaged from the corrosion.

You need to remove the slave cylinder, clean up and polish the bore, then install new seals.

Then switch to DOT 5 (that ought to start a nice tangent to this thread).

DavidR.

[LA Mike]

Then switch to DOT 5 (that ought to start a nice tangent to this thread).

DavidR.

David,

Why switch to DOT5... you must have a reason to use that four letter work around here 

LA MIKE

[SlowOldGuy]

Mike,
Just stirring the pot a little.  :-)

DavidR.

[weymouth399]

Mike,
Just stirring the pot a little.  :-)

DavidR.

Isn't that how you make rope

[Marsh White]

Then switch to DOT 5 (that ought to start a nice tangent to this thread).

DavidR.

David,

Why switch to DOT5... you must have a reason to use that four letter work around here 

LA MIKE

Mike, 2 years ago when you and I were ripping it up on the long 25 mile twisty stretch to leggit, I boiled my brake fluid and had no front brakes for the last 2 miles...it was freaking scary!  There was new Dot3/4 synthetic in there...and they were newly bled.  Of course, I could have still had an air bubble or two in there...  That alone would make me want to switch (DOT 5 has a higher boiling point than DOT 3 or 4)...though there is a lot of work to do so.  And honestly - that is the only time in my life that I have boiled the front brake fluid before.  Of course, the fact that DOT 5 does not eat paint is a nice feature as well.

[turbocamino]

If you just cleaned/replaced the outer seal, then you didn't address the real problem.  The inner bore is probably corroded and teh inner seal has hardened or been damaged from the corrosion.

You need to remove the slave cylinder, clean up and polish the bore, then install new seals.

Then switch to DOT 5 (that ought to start a nice tangent to this thread).

DavidR.

Sorry for not being clearer...i did both seals and am wondering if maybe the piston seal can and was put on backwards? ...i looked at the fiche here and it appears theres a leading edge to the seal that goes into the piston first.... will look tommarow A:M to  be sure.

[SlowOldGuy]

The CUP (hollow side) of the seal should face the fluid.  That's so fluid pressure can get into the cup and force the outside edge onto the face of the cylinder bore to keep it sealed.

Did you polish the bore and remove ALL corrosion?  Was there any corrosion?  Did you remove ALL corrosion/rust from the groove in the Piston?

You might also want to rebuild the master cylinder sometime soon.  At least inspect it to make sure it's not leaking too.


DavidR.

[the fan]

not a fan of dot 5 myself coming from a wet/humid part of the country. I raced 2 seasons for ATK (dealership level with limited factory support) and the bikes I ran used dot 5 as the OEM fluid. I had no end of trouble with fluid contamination and boiling fluid(actually boiling the accumulated water that collects at the hottest part of the system) It was common to completely drain the system after every event to prevent issues. then again I was racing off road, not sport touring so your results may vary....I wound up swapping it out for Dot 4 fluids.

I experimented with DOT5.1 fluids when I was involved with a KTM shop but decided that the added cost and difficulty in sourcing just was not worth it to ME. but the DOT5.1 fluids do a great job. They are also compatible with DOT 3/4 fluid systems but not DOT5. You do have to drain and flush the system when you switch but its not as involved as the 3/4 - 5 swap.

I currently run Motul RBF600 in my bikes as I tend to abuse the brakes and its 593 degree dry/312 degree wet boiling point meets my needs. In the race bikes we run Motul RBF660 (617 degree dry/400 degree wet) and rarely have issues running A, B, and C superbike expert classes with a stock rotor/caliper GSXR600.


for reference:

dot 3 fluids meet minimum 401 degree dry/284 degree wet
dot 4 fluids meet minimum 446 degree dry/311 degree wet
dot 5 fluids meet minimum 500 degree dry/356 degree wet
dot 5 fluids meet minimum 518 degree dry/376 degree wet

[racerman_27410]

well since Bill posted the temp requirements why not ratings for some popular brake fluids.


DRY WET
Castrol LMA DOT 3/4 446 311
Ford Heavy Duty DOT 3 550 290
ATE Super Blue Racing 536 392
ATE TYP 200 536 392
Motul Racing 600 585 421
Castrol SRF 590 518
Performance Friction 550 284


Kookaloo! 

[rktmanfj]

not a fan of dot 5 myself coming from a wet/humid part of the country. I raced 2 seasons for ATK (dealership level with limited factory support) and the bikes I ran used dot 5 as the OEM fluid. I had no end of trouble with fluid contamination and boiling fluid(actually boiling the accumulated water that collects at the hottest part of the system) It was common to completely drain the system after every event to prevent issues. then again I was racing off road, not sport touring so your results may vary....I wound up swapping it out for Dot 4 fluids.

I experimented with DOT5.1 fluids when I was involved with a KTM shop but decided that the added cost and difficulty in sourcing just was not worth it to ME. but the DOT5.1 fluids do a great job. They are also compatible with DOT 3/4 fluid systems but not DOT5. You do have to drain and flush the system when you switch but its not as involved as the 3/4 - 5 swap.

I currently run Motul RBF600 in my bikes as I tend to abuse the brakes and its 593 degree dry/312 degree wet boiling point meets my needs. In the race bikes we run Motul RBF660 (617 degree dry/400 degree wet) and rarely have issues running A, B, and C superbike expert classes with a stock rotor/caliper GSXR600.


for reference:

dot 3 fluids meet minimum 401 degree dry/284 degree wet
dot 4 fluids meet minimum 446 degree dry/311 degree wet
dot 5 fluids meet minimum 500 degree dry/356 degree wet
dot 5 fluids meet minimum 518 degree dry/376 degree wet

FWIW, I've used DOT5 in the front brakes of my FJ (with both the stock and the current R1 systems for several years now, with no apparent ill effects.  I've got a new braided clutch line going on soon, and can't think of any good reason not to use it there, too.  We'll see.

That what you were lookin for, David?       

Randy T
Indy

[the fan]

well since Bill posted the temp requirements why not ratings for some popular brake fluids.


DRY WET
Castrol LMA DOT 3/4 446 311
Ford Heavy Duty DOT 3 550 290
ATE Super Blue Racing 536 392
ATE TYP 200 536 392
Motul Racing 600 585 421
Castrol SRF 590 518
Performance Friction 550 284


Kookaloo! 

Makes perfect sense. Pretty impressive differences in the brands listed. wonder who carries the castrol SRF?

[the fan]

I experimented with DOT5.1 fluids when I was involved with a KTM shop but decided that the added cost and difficulty in sourcing just was not worth it to ME. but the DOT5.1 fluids do a great job. They are also compatible with DOT 3/4 fluid systems but not DOT5. You do have to drain and flush the system when you switch but its not as involved as the 3/4 - 5 swap.

I currently run Motul RBF600 in my bikes as I tend to abuse the brakes and its 593 degree dry/312 degree wet boiling point meets my needs. In the race bikes we run Motul RBF660 (617 degree dry/400 degree wet) and rarely have issues running A, B, and C superbike expert classes with a stock rotor/caliper GSXR600.


for reference:

dot 3 fluids meet minimum 401 degree dry/284 degree wet
dot 4 fluids meet minimum 446 degree dry/311 degree wet
dot 5 fluids meet minimum 500 degree dry/356 degree wet
dot 5.1 fluids meet minimum 518 degree dry/376 degree wet

made a boo boo...the last one should have been DOT5.1

[simi_ed]

Well, since we've got the ruler out & we're measuring ...
Amsoil's Dot 4 Racing Fluid has Dry rating of 304°C (580°F) and a Wet rating of 210°C (410°F).

Of course, it's available from your friendly local Amsoil dealer/FJ owner