ciderman

Active Member

• Mar 27, 2019

• #1

Is it just us - or is it everyone who has so much difficulty bleeding the rakes on 109?
3 of us with a sealey pro brake bleeding kit spent a day and a half trying to get a good pedal.
between us we had 142 years of experience- yet we still struggled and did it time after time until exhaustion set in and a half decent pedal was achieved.
Who knows the secret?

 

tottot

Well-Known Member

• Mar 27, 2019

• #2

When I had a 109 I changed the set up on the front 2 slave brakes. As standard flexi goes to top slave and a hard pipe then takes fluid to the bottom slave, air likes to stay at the top.
So I swopped pipes over. The flexi stays at a bracket at the top,hard pipe to lower slave,hard pipe back to top slave,bleed nipple now on the top slave where the air wants to go.

 

ciderman

Active Member

• Mar 27, 2019

• #3

we were talking about that.
Is there risk of the pipe being damaged off road?

 

Chopz

Member

• Mar 27, 2019

• #4

Had a crappy brake after brake overhaul on my 88 but that was the britpart shoes
After a few hundred miles they bedded in the the brake pedal travel is now good

 

tottot

Well-Known Member

• Mar 27, 2019

• #5

Keep the extra pipe tight to the back plate alongside the other and should be good. Adjust all brakes up before bleeding.

 

T

Tall Ratbag

Active Member

• Mar 27, 2019

• #6

tottot said:

Adjust all brakes up before bleeding.

Click to expand...

It's actually better to do the opposite of this.

Although it sounds odd, the problem stopping the front brakes on 109s being bled is a pocket of air behind the extended pistons in the wheel cylinders.

If you adjust the brakes fully off, this pushes the pistons back in the wheel cylinders, and forces the air pocket out of the cylinders into the brake pipes - from where the air can be pushed out using either a brake bleeder, or even just the brake pedal. You should see a stream of bubbles released when you do this, While the air pockets are in the wheel cylinders, no amount of pumping or bleeding will shift them.

Obviously, you'll need to re-adjust the brakes afterwards to get a good pedal back!!

 

R

rob1miles

Well-Known Member

• Mar 28, 2019

• #7

Agreed, I hate the job, but it goes OK. Loosen all the adusters to bottom the cylinders, easybleed, just crack the nipple, tight fitting bleed tube kept under the fluid level, bleed fluid level above nipple. If you are feeling keen take the nipple out and grease the threads so air can't get back up while you are bleeding. If the pedal is soft when the air is out its the master cylinder. Reason I sorted the bleeding was that my probelm was the master cylinder!

 

ciderman

Active Member

• Mar 28, 2019

• #8

Ahhh!

 

blue beasty

Leaks an prone to bits dropping off

• Mar 28, 2019

• #9

If I've had the drums off anyway I clamp the piston back in the slaves and bleed before reassembly.

I've also bled the top cylinder at the link pipe but you need lots of rags fer that

 

peter8315

Active Member

• Apr 2, 2019

• #10

I agree with totott, you must have the bleed nipple at the top, so feed in down to the bottom and the return to top cylinder otherwise air gets trapped at top

 

R

rob1miles

Well-Known Member

• Apr 2, 2019

• #11

Mine is as per std, bleed nipple at teh bottom on the TLS brakes, it bleeds OK with an easibleed, so long as the adjusters are backed off fully to cut the volume.

 

ciderman

Active Member

• Apr 8, 2019

• #12

Ok Thanks