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Discussion Starter · #21 ·
Great idea on removing the lines at the pumps. The front pump has great supply of brake fluid to the pump but it is like syrup, and nothing comes out the top at all while cranking the engine over. I removed the carbs, I cannot get the supply line off, I need to bring a stubby wrench home. But I removed the top line, cranked the engine over and I get a little pulsing of brake fluid coming out but not a whole lot. How much should be coming out? They look like a rusty mess. The front one needs to come out for sure. Maybe the push rod is broken or the pump just corroded.
 

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How are the filters? If clogged you will get little or no fluid from the pumps. Have a good look at the feed hoses from the reservoir to the pumps, are they spongy or weeping through the surface? Guys mistakenly use fuel hose for them which brake fluid attacks causing them to swell and sometimes close off internally. EPDM hose must be used for that application, 3/8ths heater hose is what is required. The pump plungers can stick up from corrosion, as your car has sat unused for so long they may have gone up on the first stroke and stuck there so don't assume the pushrod is broken. Had a pump like that on a client's car just last week. You should get a good six inch spurt if the pump is getting unrestricted fluid from the reservoir.
 

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As others have said, start at the reservoir.

These cars - all elderly cars - suffer from catastrophic deterioration of the brake fluid when not changed or left unused for long periods. It absorbs water from the air. I am half-way through the repair of a Shadow which had been little used for several years. The reservoir filter were collapsed, and the fluid had black gunge and yellow jelly in it. Nearly all the brake pistons were rusted solid because hoses or valves were clogged preventing the pistons from relaxing off, which causes the brakes to rub, which causes the caliper assemblies to get VERY hot, which causes the dust seals to distort or even melt, which lets water into the ends of the caliper cylinders, which cause them to grip the pistons tight, or some other sequence of deterioration in the same loop. It must all be good, or it "snowballs" into this condition - one problem causing another. Note: the reservoir lid is held on with 2BA screws - some of them have nuts which are easily dropped and lost.

DIY repairs to this area will save a lot of money, but you must be prepared for problems such as stuck/rusted pipe joints. HINT: only ever use 6-point flare-nut spanners on hydraulic joints - NEVER 12-point, especially if the nut is rusty - it will round off the hexagon and the only solution may be to cut the pipe. A long-term solution is to use stainless-steel replacements in repairs.

I solved the problem many years ago by using DOT5 silicone brake fluid, and have not suffered from these problems since. (Note - not DOT5.1). Some people will say "No, no, no!" but the rubbers used in seals today are very different to the material used in the early days of the Shadow. And the silicone oil discourages rust and does not attack paint, though sprayers hate it - it is difficult to clean off painted surfaces. (Discuss.)

Incidentally, I think that brake pads absorb water too. It would explain why brake pads shatter in a characteristic way when brake systems suffer in the way described. When the brakes are applied for the first time the water in the pads boils and shatters the pads. Anyone else noticed that?

Alan D.
 

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Discussion Starter · #24 ·
Thanks again for the info!! Tonight I took apart the reservoir and sucked out the brake fluid. It was like you all stated, full of sludge under the plates. The filters are collapsed.

Question. Would it be ok for me to put some dot3 or dot5 in just for testing purposes, since I'm going to be replacing the accumulaters valves and hoses etc?
 

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There would be no point in testing right now. You will be moving the **** around. You have a way to go to clean,rebuild and replace. Wait until everything is done and use brake fluid to test and check for leaks.
 

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No harm in doing that, use DOT 3 or 4 and see if you get any pressure build up. Don't use DOT 5 silicone! Bear in mind that once you have it cleaned and refilled and the engine running again the muck in the rest of the system will be pumped back into the reservoir so if the filters are ripped it will be pumped into the pumps. If the filters are already ripped then it doesn't really matter as the pumps will already be full of muck and you're going to have to strip and repair all of the brake system anyway to make the car safe to drive. Might give you some short term satisfaction if you can get it to build up some pressure after cleaning the reservoir but don't think it will be safe to drive without a major overhaul.


.
 

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Discussion Starter · #27 ·
After cleaning the reservoir I put regular brake fluid in for now because I needed to move the car in my shop while waiting for parts. Now only brake system 1 red light stays on and the car has some braking. I was glad to see that. I'm guessing there is an issue with the front hydraulic pump. It has brake fluid supply but nothing comes out. I will update this post when new parts are installed. Lastly, how are the caliper Pistons replaced? Do you need new seals? I've never replaced Pistons before. Thank you.
 

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The calipers have to be "split". There are 2 internal square cut galley seals that must be replaced (pricey) The pistons may be rusted and depending on condition, replaced. There is a piston seal and external dust seal that gets replaced. The bleeder should also be replaced as well to insure a good fit. Are you familiar with the hydraulic system and which bleeders are on what cicuit? It is important to know these things. The Marinus website has an animated hydraulic map to understand the system. When the calipers come off, the caliper hoses get replaced.
 
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