Front brakes wont hold
#1
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So I replaced my accumulator ball with a used one from ebay and bled the brakes all around. Some really dirty fluid came out. However I am still having some problems. The Brake and anti lock brake lights still come on when pressing the brakes. Also the front brakes wont hold pressure, the rears hold it fine. When pressing the brakes the fronts work but will give up after a few seconds. Could it be the new accumulator ball still?
#2
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So I replaced my accumulator ball with a used one from ebay and bled the brakes all around. Some really dirty fluid came out. However I am still having some problems. The Brake and anti lock brake lights still come on when pressing the brakes. Also the front brakes wont hold pressure, the rears hold it fine. When pressing the brakes the fronts work but will give up after a few seconds. Could it be the new accumulator ball still?
It is quite possible that the used accumulator is not working properly. You can test it by following the procedure in the manual I am attaching.
From your symptoms, I wonder if there is a problem with the master cylinder seals or one or both of the front calipers.
Cheers,
Don
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#3
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Hi cougarman,
It is quite possible that the used accumulator is not working properly. You can test it by following the procedure in the manual I am attaching.
From your symptoms, I wonder if there is a problem with the master cylinder seals or one or both of the front calipers.
Cheers,
Don
It is quite possible that the used accumulator is not working properly. You can test it by following the procedure in the manual I am attaching.
From your symptoms, I wonder if there is a problem with the master cylinder seals or one or both of the front calipers.
Cheers,
Don
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The diaphragm or bladder is designed to hold very high pressure, 1,200-1,450 psi (83-100 bar), so I don't know that you would be able to deflect it by your own strength. In any event, that seems like a highly dangerous way to test it, in the event you managed to puncture the diaphragm and have the escaping nitrogen force your blunt object out at high speed, like an air rifle. If I recall correctly, the manual test procedure involves counting the number of brake pedal depressions before the pedal goes hard and comparing that number to the specification.
Cheers,
Don
Last edited by Don B; 03-04-2018 at 08:00 PM.
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#5
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The diaphragm or bladder is designed to hold very high pressure, something like 1,200 psi, so I don't know that you would be able to deflect it by your own strength. In any event, that seems like a highly dangerous way to test it, in the event you managed to puncture the diaphragm and have the escaping nitrogen force your blunt object out at high speed, like an air rifle. If I recall correctly, the manual test procedure involves counting the number of brake pedal depressions before the pedal goes hard and comparing that number to the specification.
Cheers,
Don
Cheers,
Don
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You're making progress!
I still suspect you may have a problem with your master cylinder/power actuator. You had asked about identifying a component that was seeping. If you could post a photo it might help us give you a definite identification, but in the mean time, here's the parts diagram of the master cylinder/power actuator:
![](https://cimg0.ibsrv.net/gimg/www.jaguarforums.com-vbulletin/400x427/mj4974a_a930a90cf50ea3f46a3625c578b1af0518255cd3.png)
Here's a photo I borrowed from eBay:
![](https://cimg0.ibsrv.net/gimg/www.jaguarforums.com-vbulletin/1600x900/s_l1600_b1c2780731415d72670284b70d1731e4e66d0c58.jpg)
Cheers,
Don
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cougarman (03-12-2018)
#11
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Thanks I pressure tested the lines coming from the master cylinder to the front brakes and 0 pressure. Do you know if these master cylinders get bench bled before going into the car?
Also the part that has seepage is that large metal case closer to the firewall. That has the master cylinder attached to it.
Also the part that has seepage is that large metal case closer to the firewall. That has the master cylinder attached to it.
#12
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Thanks I pressure tested the lines coming from the master cylinder to the front brakes and 0 pressure. Do you know if these master cylinders get bench bled before going into the car?
Also the part that has seepage is that large metal case closer to the firewall. That has the master cylinder attached to it.
Also the part that has seepage is that large metal case closer to the firewall. That has the master cylinder attached to it.
![](https://cimg8.ibsrv.net/gimg/www.jaguarforums.com-vbulletin/400x485/mj4983a_0986a85886d4a3837e295400898b8ed1c9b7ac2d.png)
If fluid is seeping from the housing, the rear seal of the master cylinder must be leaking fluid into the housing.
By the way, if I haven't already mentioned it, a great place to look up parts diagrams and part names and numbers is jaguarclassicparts.com, the parts service of the Jaguar Daimler Heritage Trust.
Cheers,
Don
Last edited by Don B; 03-12-2018 at 07:51 PM.
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