[KoolBreeze]

What is “normal” as far as how far back the front brake lever travels when the brakes are applied? This is an ‘88 TRX350D with drum brakes.

I’ve replaced the seals in all cylinders and bleed probably 2 pints of fluid through it. The handle stops about 1/2” before it hits the handlebar grip but I can pull it all the way to the grip without much effort. The brakes do work, I’m just wondering if I should have more lever. If I crimp the hose it’s hard as a rock with very little movement.

Anyway, just trying to get a baseline fir what to expect.

 

[LedFTed]

ya might still have air somewhere, or a seal is bypassing. did you replace master cylinder, seals? or take apart master cylinder, and clean it. old brake fluid might cause problems.
air was getting into my master cylinder. a black film would develop, an build up till the seals would skip over, and let fluid bypass. i had to clean it many time's.
i got a new kit, and extra gaskets for other parts. i haven't installed yet. health an weather. did i say, even more weather?
i dont want to give ya too much unnecessary info. just food for thought.

 

[shadetree]

did you adjust the shoes all the way out BEFORE you started bleeding the brakes ????.

 

[KoolBreeze]

I started out bleeding the brakes with clamps on the cylinders so they couldn’t move at all. Still didn’t have a rock hard lever.

Then bleed them a few more times after everything was back together and yes with the shoes all the against the drums. Used a hand vacuum bleeder and the old fashion way. Couldn’t really tell any difference. I did not rebuild the master cylinder or take it apart but if I clamp the hose past the master cylinder I get a hard lever. Can also clamp just behind the T and get a hard lever in a pump or 2, so it’s probably still got a little air in it.

I’ll zip tie the lever for a day or 2 and see how it does. Might try reverse bleeding it if that doesn’t solve it.

 

[GirlsRideToo]

I started out bleeding the brakes with clamps on the cylinders so they couldn’t move at all. Still didn’t have a rock hard lever.

Then bleed them a few more times after everything was back together and yes with the shoes all the against the drums. Used a hand vacuum bleeder and the old fashion way. Couldn’t really tell any difference. I did not rebuild the master cylinder or take it apart but if I clamp the hose past the master cylinder I get a hard lever. Can also clamp just behind the T and get a hard lever in a pump or 2, so it’s probably still got a little air in it.

I’ll zip tie the lever for a day or 2 and see how it does. Might try reverse bleeding it if that doesn’t solve it.

Here is the great advice @retro gave me. Hope something he said helps you.
I think you need to disassemble, check and clean the master cylinder. You'll be surprised how the old brake fluid turns to sticky goo. If any of this goo gets into your brakes lines you'll have trouble getting them bled properly. Be sure that rubber cup is not torn or deteriorated.
@retro said "..... adjust each adjuster wheel out tight until the brake shoes lock up the drum, then back each one off about 3 clicks, or until the drum can be rotated to line up the adjustment hole in the drum with the next adjuster wheel, using both hands. The shoes should drag hard on the drums, but not so much that you cannot turn each drum with effort. At that point the brakes are properly adjusted and ready to be bled, then driven.

If there is a small round rubber cup (with tiny slits in it) installed in the bottom of the Master cylinder reservoir, you can pry that rubber out of there carefully... before bleeding any air trapped in the Master cylinder. Don't tear it taking it out... and note how it fits in there... one side is usually cupped more than the other side is, which determines which side faces UP when you reinstall it after bleeding is complete. This step is optional... but usually helps to speed up the bleeding process a bit. Skip it if it looks too fragile to get out in one piece though."

 

[retro]

You can take the bleeder screws out and wrap the threads with teflon tape so they'll seal while loosened, then turn them back in until they're about a full turn out from seated.

Then slip some clear vinyl hose onto the bleeders, loop them up over the top of the knuckles and let the ends of them down into small containers (two clear plastic water or soda pop bottles work good) with enough brake fluid in the bottom of them to prevent the hoses from drawing air.

Then pump the master cylinder lever while using a clamp on the brake hose just downstream from the master. Lay the lid on the reservoir so you don't get squirted, but keep the reservoir full as you work. You'll soon see fluid and air bubbles rising up both clear vinyl hoses. The air and a bit of fluid will rise to the top of the knuckles then escape down into the bottles, but air won't be pulled back in on your release strokes.

Once you see decent flow through those clear hoses release your clamp near the master. Then tap on the steel lines and the Tee distribution block with a plastic screwdriver handle to dislodge the last of those tiny air bubbles while continuing to pump the lever slowly. Give the lever a couple more pulls to be sure the majority of the air is out then slide a large o-ring over the end of the handlebar and brake lever to hold it back while you snug up both bleeder screws.

Then pump a couple times until the lever is hard and open the left-side bleeder and immediately close it. Build another hard lever and repeat two more times. Then build a hard lever and loosen the right-side bleeder 3 times. Done.

TRX350Ds are always pesky critters to bleed, but this method works for me everytime.

 

[KoolBreeze]

Ok, thanks guys and gal, I’ll try your suggestions and see if I can stiffen it up some.

 

[Goober]

Ok, thanks guys and gal, I’ll try your suggestions and see if I can stiffen it up some.

Air does rise up in the hose—it collects at the highest point which is the hose where it mates to the master cylinder.

Turn your handlebar left to get the air right up against the m/c. Pry that rubber puck out and jiggle the lever—you’ll see the air bubbles rise up in the reservoir. When you got no more air you should be good.

Btw I don’t use the clamps i use a big band of hook and loop made to keep extension cords tied up. Wrap it around the lever or i get my daughter to help me

 

[KoolBreeze]

Got out there this afternoon messing with it and have succeeded in making much worse. Haha! No front brakes now at all. The seals on the master cylinder piston started leaking fluid out onto the lever. Maybe that's why I've not been able to get all of the air out yet, I don't know. It will still build pressure if I clamp off the hose with vise grips but otherwise it won't, even if you pump it several times. That seems odd to me. Maybe it only leaks when the lever released.

So I guess I'll need to rebuild the master cylinder now. Looking at the diagram on the Partzilla, it looks like I just need to the set for the piston, the separator that sits down in the reservoir, and some new crush washers,is that all?

 

[retro]

Yeah thats pretty much all there is to them. I'd take the piston out so I could inspect the cylinder before buying the new rubber parts tho. If there is any corrosion pitting in the bore it won't hold new cup seals leak-free very long. Same goes for the wheel cylinders, gotta fix any pitting before assembling them if any is present.

 

[LedFTed]

i've cleaned out that black goo many times, too lazy, to order a master cylinder kit. :smile

 

[KoolBreeze]

i've cleaned out that black goo many times, too lazy, to order a master cylinder kit. :smile

I doubt seriously that this one has ever been apart. My inability to leave well enough alone just isn't mixing too well with this 30+ year old bike. But I suppose if I've got to be doing something it may as well be tinkering with it.

 

[LedFTed]

mine is a 2000. it dont matter when air, or water gets in the fluid age wise, its still a problem..
my master cylinder, has a c-ring you remove, then the plunger, spring, an the rest comes out. i have a channel-lock tool for this, and it helps.
it works on, in ring's or out rings.
once ya got the proper tool, it helps a lot.

 

[KoolBreeze]

Got her fixed. Rebuilding the master cylinder did the trick. Didn't have any trouble getting them bled afterwards. Guess it was the source of the problem all along. Getting the seals back in the bore, especially the rear one, is a pain but a pretty easy job otherwise.

 

[GirlsRideToo]

Got her fixed. Rebuilding the master cylinder did the trick. Didn't have any trouble getting them bled afterwards. Guess it was the source of the problem all along. Getting the seals back in the bore, especially the rear one, is a pain but a pretty easy job otherwise.

Great! Now on to the next thing on your list. LOL

 

[KoolBreeze]

Got her fixed. Rebuilding the master cylinder did the trick. Didn't have any trouble getting them bled afterwards. Guess it was the source of the problem all along. Getting the seals back in the bore, especially the rear one, is a pain but a pretty easy job otherwise.

Great! Now on to the next thing on your list. LOL

Haha! That list is getting shorter and shorter. Fuel filter, spark plug, FCU, idle speed and valve adjustment is about all that's left. Kind of half scared to pull the plug, with the luck I've been having with it, it's probably seized and would end up having to pull the head!