3 replies to this topic

[dschwartz1957]

My 1968 Mini Traveller had braking problems for much of the summer driving season. I needed to pump the brakes 2 or 3 times before there was good pedal pressure, even though the fluid level in the master cylinder stayed constant. Adjusting and bleeding the brakes did not eliminate the problem, and I was unable to get the left front and left rear wheels to fully lock. I removed all four drums to investigate.

 

The left rear brake adjusters were worn and small chunks of metal were missing. I plan to replace the adjuster and wedges with http://www.minispare...ic/17H7620.aspx The rear shoes were replaced 12 years ago and have over 4 mm of friction material remaining.

 

The left front shoes were worn to 1.98 mm and 2.3 mm. The right front shoes were around 2.6 mm. The front pads and wheel cylinders are 14 years old, and two cylinders had a tiny amount of fluid under the boots, and some staining on the backplates. I plan to replace all four wheel cylinders and both sets of shoes.

 

The Mini Spares parts diagram shows a "front brake shoe retainer spring", which my car never had during my ownership. The part is required with the 0.9375" bore size wheel cylinders (GWC126 / GWC127) which I plan to install. http://www.minispare...ck to catalogue

 

I have read through the Haynes Manual and the Mini Workshop Manual and can't figure out how the little retainer springs are installed. The photo on the Mini Spares link I posted shows the spring going through a hole in each brake shoe just below the wheel cylinder piston, but the details are obscured by a logo watermark. The photo is attached below for your convenience.

 

Does anyone have a picture or good diagram they can post showing how the retainer springs are installed?

 

Thank you,

 

David Schwartz

Framingham, Massachusetts

 

Attached Files

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Edited by dschwartz1957, 08 November 2024 - 02:52 AM.

[Spider]

I don't seem to have a photo or diagram that shows how they are when fitted, but they are quite straightforward to fit up. These are of course, for Twin Leading Shoe Brakes, which your 68 Traveller should have.

With them missing, that could well be part of the issue you are having with the need to pump to get a peddle. The adjusters in these Brakes move and hold the Cylinder end of the shoes out to a point just on drum contact. Because they are adjusted at that point, the Pistons in the Wheel Cylinder also need to be held resting on the frame of the shoe. Without something in there to pull and hold the Piston in contact with the Frame of the Shoe, the Pistons, particularly those on the Trailer side, will self retract back in to the Cylinder, especially with road vibration. The other item that maybe missing is a Residual Pressure Valve, these are inside the Master Cylinder and retain around 5 - 10 PSI in the system to also assist with keeping the Pistons held out in all Wheel Cylinders.

[Lplus]

My 1968 Mini Traveller had braking problems for much of the summer driving season. I needed to pump the brakes 2 or 3 times before there was good pedal pressure, even though the fluid level in the master cylinder stayed constant. Adjusting and bleeding the brakes did not eliminate the problem, and I was unable to get the left front and left rear wheels to fully lock. I removed all four drums to investigate.

 

The left rear brake adjusters were worn and small chunks of metal were missing. I plan to replace the adjuster and wedges with http://www.minispare...ic/17H7620.aspx The rear shoes were replaced 12 years ago and have over 4 mm of friction material remaining.

 

The left front shoes were worn to 1.98 mm and 2.3 mm. The right front shoes were around 2.6 mm. The front pads and wheel cylinders are 14 years old, and two cylinders had a tiny amount of fluid under the boots, and some staining on the backplates. I plan to replace all four wheel cylinders and both sets of shoes.

 

The Mini Spares parts diagram shows a "front brake shoe retainer spring", which my car never had during my ownership. The part is required with the 0.9375" bore size wheel cylinders (GWC126 / GWC127) which I plan to install. http://www.minispare...ck to catalogue

 

I have read through the Haynes Manual and the Mini Workshop Manual and can't figure out how the little retainer springs are installed. The photo on the Mini Spares link I posted shows the spring going through a hole in each brake shoe just below the wheel cylinder piston, but the details are obscured by a logo watermark. The photo is attached below for your convenience.

 

Does anyone have a picture or good diagram they can post showing how the retainer springs are installed?

 

Thank you,

 

David Schwartz

Framingham, Massachusetts

Part no 27H3753 on the minispares site.  The blurb even mentions having to pump the pedal.  They are installed in the shoe before fitting, Hook the large hook throught the hole in the shoe, from the backplate side,  pull the small tang through the hole as well and twist the big hook away from the end of the shoe for fitting.  When the shoes are in place, twist the hook back round, pull out whilst holding the shoe against the backplate and insert the end of the hook in the hole in the piston

 

edit - one other thing to check is that the adjusters are stiff in rotation enough to hold the shoes close to the drums against the long springs pull.

Edited by Lplus, 08 November 2024 - 07:21 AM.

[timmy850]

My experience with drum brakes all round is you really need to start with a new, adjusted and optimised system if you want them to work. Once mine were sorted the pedal was firm from the top, and an emergency stop would lock both fronts evenly

Make sure all the wheel cylinders move freely and aren’t seized. Replace all the old rubber brake hoses. Replace all the shoes with new ones and make sure the drums aren’t worn oversize. Adjust the drums (with the front end rotate the adjusters tighter in the direction the wheels spin when going forward) tight enough so the wheel will do less than one spin freely before stopping. Press the pedal down a few times then adjust again once the shoes are centred.