front breaks stick on

[bobandjaneburden]

marina base ,rear off side wheel cylinder sized solid so fitted a new one. went for a run and the rear wheels are okay, but both the front breaks are stuck on. after 2 hours they release . i can not understand why both stay on the rear breaks are fine. thanks for any help.

[Ye Ol Ripper]

Time for a front caliper rebuild including new pistons
Source the rebuild parts from big redd on eBay. Request extra long bleed. Nipple's as their default supplied nipples are too short.

[bobandjaneburden]

Time for a front caliper rebuild including new pistons
Source the rebuild parts from big redd on eBay. Request extra long bleed. Nipple's ads their default are too short

thanks for the link.

[Ye Ol Ripper]

I also replaced the front and rear flexible hoses . I found that due to their age the internally collapse so as only to allow brake fluid to flow in one direction . So to test assuming you don't have a compressor airline, remove the 2 hoses and see after draining off the brake fluid fully ,whether you can blow through with something similar to a car foot pump with a tapered airbed adaptor . The hoses are UNF thread. I used early Landrover Defender hoses on mine that are a touch longer than the Marina hoses.

[duncan]

Hoses collapsed inside - now THAT sounds more likely than the calipers sticking

[rhysnolan]

The "one way valve" thing is not uncommon. I had braided hoses made before doing anything else with the car George now has. Full set was about £30

[greyV8pete]

Both calipers seized at the same time? Both front hoses collapsed at the same time? Both release after 2 hrs? Unlikely coincidence. I would be looking at the master cylinder/ valve seals and only for a collapsed hose if there is a common one between the master cylinder and any Tee that splits the feed to the front calipers.

[MOC Chair]

I had a similar problem with a Landrover but this was over 40 years ago and the master cylinder wasn't a dual circuit one so it affected all the brakes. As with your car it gradually released. A new master cylinder cured the problem.

[Ye Ol Ripper]

In addition to checking the above. I did once come across an unusual cause that took a long time to locate. It was on a Citroen zx( conventional brakes not LHM ) The brake lines travelled across the bulkhead and included at least 2 right hand bends as the metal pipe turned back on itself. (I guess due to the car originally being designed as a lhd car).

The cause was found to be dirt from inside the brake fluid container on the master cylinder. The dirt had floated inside the metal brake line by one of the bends. That acted as a 1 way valve holding the brakes on slightly. After draining the fluid out , i tried blowing through the master cylinder filler & then in reverse from the pipe ends that the brake hoses connect to with an airline. I saw a piece of dirt fly out the master cylinder reservoir.
No problems after that .
So an additional scenario to rule out.
(That info/tip will not be found in any workshop manuals or forums)
I hope its of value?