Thread: Bleeding 11" brakes

Saga continues lol. So i again tried bleeding it, this time followed manual method...
1) slacken cam snails right off
2) conected hose to cylinder nipple and opened
3) pumped pedal, each stroke i pumped quickly
4) closed nipple when fluid went about 1/2 down the reservoir (about 4 pumps)
5) readjust cams until shoes starting to drag

No difference, did this for all 4 wheels, starting from closest to furthest (front right, front left, rear right, rear left) as manual states start from SHORTEST route first.

I also inspected the master cyl rod and pedal freeplay. To me the rod looks fully extended out as i pulled on the rod and there was hardly any more left, and yes i did slacken off the pedal stop bolt.

I guess next step is to do John's technique of clamping off 3 hoses to determine if any particular side has issue (front). Can i use a standard small C clamp for this with both faces clear of burs etc? Is there any possible damage to inside the hoses by squashing them given its not designed for this?

Failing all that ill do your trick Colin, see if shoes are the culprit. FWIW, I Googled this issue (pumping pedal) and looks like this is a common issue with bleeding brakes. So perhaps im not that incompetent after all

I went trough a similar issue like this with an 88 with standard 10" brakes a while back when I was getting it ready for a RWC.
Normally I have never had any trouble getting a high/hard pedal. I think the fluid just ended up like a milk shake from all the pumping.
In the end I drained all the fluid out, then cracked all the bleed nipples a smidge and kept topping the master cylinder up every so often.
I do use DOT 5 Silicone brake fluid which can be more susceptible to aeration, but DOT 3 and 4 are not immune from it. The less hammering you have to do on the brake pedal trying to bleed the system, the less chance of aeration.
Like others such as Inc, Collin, Homestar, etc., have pointed out, firstly you need the shoes/linings radiused to the drums.

I know where you are coming from, it's bloody annoying and time consuming.

Good luck.
Cheers, Mick.

Originally Posted by Cap

Saga continues lol. So i again tried bleeding it, this time followed manual method...
1) slacken cam snails right off
2) conected hose to cylinder nipple and opened
3) pumped pedal, each stroke i pumped quickly
4) closed nipple when fluid went about 1/2 down the reservoir (about 4 pumps)
5) readjust cams until shoes starting to drag

No difference, did this for all 4 wheels, starting from closest to furthest (front right, front left, rear right, rear left) as manual states start from SHORTEST route first.

I also inspected the master cyl rod and pedal freeplay. To me the rod looks fully extended out as i pulled on the rod and there was hardly any more left, and yes i did slacken off the pedal stop bolt.

I guess next step is to do John's technique of clamping off 3 hoses to determine if any particular side has issue (front). Can i use a standard small C clamp for this with both faces clear of burs etc? Is there any possible damage to inside the hoses by squashing them given its not designed for this?

Failing all that ill do your trick Colin, see if shoes are the culprit. FWIW, I Googled this issue (pumping pedal) and looks like this is a common issue with bleeding brakes. So perhaps im not that incompetent after all

Carlos I may be wrong here but I was led to believe shoes need to be locked onto drums with snail cams before bleeding is started

Cheers Paul

Originally Posted by bemm52

Carlos I may be wrong here but I was led to believe shoes need to be locked onto drums with snail cams before bleeding is started

Not normally needed. If correctly adjusted brakes should bleed OK.
Every 2-3 years I bleed the brakes on my fleet to replace the fluid, never lock the shoes onto the drums (but do take the opportunity to adjust correctly before bleeding).

Colin

Originally Posted by Cap

.....

I guess next step is to do John's technique of clamping off 3 hoses to determine if any particular side has issue (front). Can i use a standard small C clamp for this with both faces clear of burs etc? Is there any possible damage to inside the hoses by squashing them given its not designed for this?

.....

I have some purpose made clamps for brake hoses (can't remember where they came from but it would have been one of the regular places like Supercheap, Repco etc). These clamp the hose between two curved 'anvils' with a radius of about 5-10mm. Although these are screw clamps, I have seen pictures of ones made from two 20cm lengths of 10mm steel hinged together at one end and with a ring that can be put over the other end to hold them together - they are used like a pair of pliers. I have also used vicegrip type clamps with rounded jaws intended to hold bits of steel together when building my house. I think the secret to avoiding damage is to not have sharp edges to the bits in contact with the hose, so a conventional G-clamp would not be suitable.

I tried both techniques, snails clamped close (but not locking shoes) and loose to allow the cylinders can 'pump' the air out.

As for the clamps, I have some small RHS with the rounded edges that I can use with grips then. This will provide a smooth profile on the edge as you state John.

Hopefully I can then narrow the problem to one area, or this doesnt change then it has to be the M/C. Ill report back with progress.

Its done! Ok so I thought more about it and came to conclusion that the pedal travel and subsequent pumps should be brake adjustment. So i went around and re-adjusted all 4 corners, and found the two rear brakes inner snails where not one click from tight (i think i may of missed these on previous adjustments). Adjusted these and now i have the travel on the pedal on the first press.

To say im over the moon is an understatement! Thanks again for all your posts, i certainly learned a lot and now should have no hassles in future.