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122 Brake issues

MikeJr.

MikeJr.

Gloss Boss
300+ Club
Joined
Oct 10, 2003
Location
Acworth, GA 30102
Ok, I've replaced the front calipers, rear wheel cylinders, and the master cylinder. I have bleed the brakes twice, and adjusted the rear drums, but I still have to double pump the brakes to get good pedal. Should I just need to keep bleeding the brakes until it feels right?

1965 122
 
I had a similar issue when I just redid my rears. It took 2 rounds of bleeding, followed by a few laps around the block of pumping the brakes for everything in the rears to seat, then another round of bleeding. How much pump the first time? When I would first hit the brakes I had about 2.5-3" of pedal travel, then the 2nd pump would be more like 1.5-2". Now after a few days of driving, It's solid at 1.5-2".
 
Is your car equipped with an original Girling or Lockheed hydraulic brake booster?

Air likes to get trapped in those units and it can be difficult to get the system bled properly.

Try bleeding at the booster brake outlet line and/or at the brake line junction block on the firewall below the heater box.
 
cwdodson88 said:
I had a similar issue when I just redid my rears. It took 2 rounds of bleeding, followed by a few laps around the block of pumping the brakes for everything in the rears to seat, then another round of bleeding. How much pump the first time? When I would first hit the brakes I had about 2.5-3" of pedal travel, then the 2nd pump would be more like 1.5-2". Now after a few days of driving, It's solid at 1.5-2".
Click to expand...
I think this is what I'm going to have to do.


planetman said:
Is your car equipped with an original Girling or Lockheed hydraulic brake booster?

Air likes to get trapped in those units and it can be difficult to get the system bled properly.

Try bleeding at the booster brake outlet line and/or at the brake line junction block on the firewall below the heater box.
Click to expand...
No brake booster. Just the master.
 
Are the parking brake cables over adjusted?

If they are, the top of the brake shoes are being held away from the wheel cylinders which will cause a low pedal.

Try de-adjusting the parking brake cables until they are slack and then see if the rear brakes need more adjustment.
 
MikeJr. said:
Did you get much air the second time around?
Click to expand...

Not really, some tiny bubbles. The first round was more or less just a gravity bleed while I drank a beer. Hooked up a clear tube to the bleeder that went into a bottle with some fluid in it, and cracked it open with the pedal at rest. Let it go until the master dropped below half and refilled, let it drop again to half and refilled, then pushed and held the pedal about 2" down and tightened the bleeder, pumped the brakes and did the other side. Then the 2nd round was a "push>crack>tighten>release" so pushing the pedal down and sticking a rod between the pedal and the seat, cracking the bleeder, then tightening the bleeder, and removing the rod to bring the pedal back to rest.
 
planetman said:
Are the parking brake cables over adjusted?

If they are, the top of the brake shoes are being held away from the wheel cylinders which will cause a low pedal.

Try de-adjusting the parking brake cables until they are slack and then see if the rear brakes need more adjustment.
Click to expand...

You know you might be on to something. I did notice the e-brake was a little tight.
 
I adjusted the e-brake and the rear brakes but it still feels about the same. I'm going to try a and bleed them again this weekend.
 
New shoes, old drums?. Does the radii of the shoes match the drum? If the shoes are a smaller radii than the drum you are using pedal travel to bend them to the drum radii. It doesn't have to be much.
 
As a data point: In 2003 or so picked up a 1966 122S on a whim for $200. Among its deferred maintenance issues was a brake pedal which needed a double pump for the brakes to be firm. over a weekend I went through the system several times bleeding, etc. with no success. A couple weeks later while driving across the city, discover to find the brakes work fine on the first pump. That is when I realized the hand brake had been left on. Later that day went under the car, adjusted the rear parking brakes and from then on the brakes worked fine.

Try driving with the hand brake on a couple clicks to see if the pedal feel changes, that should either point to or eliminate the rear parking brakes as the source.

99625562_8aaf731e07_z.jpg
 
5 year update :-P

Replaced the rear rubber brake hose, and blew out all the hard lines with brake cleaner and compressed air, and bleed the brakes several time until there was zero air. Then I followed the process for rear adjustment starting at minute 12:00 in this video and it finally solved the problem. Been driving the car all this time pondering how to fix this. Kinda dumb but I gave up to be honest. Hopefully this helps someone else having the same issue.

<iframe width="560" height="315" src="https://www.youtube.com/embed/E-wghTDCPCM" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
 
Last edited:
Thanks for the update. The brakes in my 67' 220 have always been pretty bad despite having good pedal feel and replacing both cylinders and calipers. Getting ready to do the pads and shoes just to see if that improves them any.
 
The 122/1800 brakes should be more than adequate for the weight of the car even without a working brake booster. Some of the late 1960's/early 1970's Jaguars came with the same sizes and numbers of front brake caliper pistons in their calipers.

What brand of brake pads and brake shoes are you using.

How old are the brake hoses?

jnderr said:
Thanks for the update. The brakes in my 67' 220 have always been pretty bad despite having good pedal feel and replacing both cylinders and calipers. Getting ready to do the pads and shoes just to see if that improves them any.
Click to expand...
 
planetman said:
The 122/1800 brakes should be more than adequate for the weight of the car even without a working brake booster. Some of the late 1960's/early 1970's Jaguars came with the same sizes and numbers of front brake caliper pistons in their calipers.

What brand of brake pads and brake shoes are you using.

How old are the brake hoses?
Click to expand...

I think they are OEM pads, not sure about the shoes, they seemed in good shape when I replaced the calipers and shoes a couple of years back.

The hoses are IPD stainless/teflon hoses from the early 2000s
 
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