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Andrew Mclintock
Yet to post message
Username: amacka

Post Number: 1
Registered: 09-2021
Posted on Tuesday, 19 October, 2021 - 13:40:   Edit PostDelete PostView Post/Check IP

Iíve had my Shadow for a few years now and Iím surprised and very grateful for the large amount of technical information available on-line. This forum has been especially useful, so I thought I should contribute. Iíve been around old cars for a long time, but not English ones and not Rolls Royceís. The thought of doing any work on one was a bit daunting. I managed to avoid this for a few years until a leaking accumulator value forced me to roll up my sleeves and have a go.

I thought I would share my experience along with some of the things I learnt along the way in the hope it might help someone else in a similar situation. Apologies for the length of the post but there was a bit to cover. I ended up overhauling both brake pumps and both accumulator valves. The spheres were good, so I left well enough alone. I determined this by running the engine for 5 minutes to pressurise the system and then pressing the brake pedal until the red warning light some on. I got about 80 pumps, anything under about 40 my understanding is the spheres need to be repressurised. My car is late 69 so doesnít have the later disposable spheres.

Starting with the pumps, I bought 2 rebuild kits and a removal tool. The front pump came off without too many issues. To remove the rear pump, I ended up removing the Ďram hornsí and carbs. It turns out these come off as a complete assembly. It took a while but gave me much better access to the rear pump. The pumps themselves came apart easily, I replaced all 3 o-rings. The lower part of the outer section of both pumps were starting to show signs of corrosion, the rear was worse than the front. I was able to get new outer housings without too many problems or great expense. I took my time, but everything went back together without too many problems. Re-connecting fuel lines was a bit tedious but I got there in the end.

The accumulators where a bit more of a challenge. I removed the front passenger side wheel to get access and put the car on stands. Removing them wasnít hard, more awkward than anything. Disconnecting the return line to the reservoir essentially drains it, think I got about 2 litres of fluid. Separating the spheres from the valves wasnít easy. I had read that one approach was to hold the sphere and hit the valve body with a soft faced mallet. I tried this but no luck. I tried holding the sphere is a vice as well, no go. In the end I held the spheres by hand and used a normal hammer and gently as I could. This worked and didnít do any obvious damage, but I suspect may have caused an issue down the track. I wouldnít use this method again, but I havenít found where to get the correct spanner to remove them either. Iím not sure what the right answer is but would be very interested in what others have done.

I got a length of 1 inch hex stock via eBay to remove the retaining socket on the end. They came out ok but didnít feel very smooth as they undid. I carefully removed the insides of the valves and put rebuild kits in both. I found the o-ring nearest the retaining socket on value that was leaking had signs of damage, they looked like small rips in the rubber, but it was still a complete o-ring.

Everything was going ok until almost the very end when I tried to screw in the retaining socket. Neither wanted to screw back in, they would either bind up or pop out. I was doing this by hand and not using too much force, the last thing I wanted to the damage the threads. With the contents of the valve body installed there is a spring pushing back on the retainer so I removed the inner workings to prove they would screw in. Same issue on both. The treads didnít look great but no obvious damage. In the end I took them to a local engineering firm and waited several weeks to see what could be done. To their credit they fixed them both. They said they used a thread file to restore the threads, until then I didnít know there such things, I now have a set. They also suggested that my removal method with the hammer may have contributed to the issue. I didnít beat the hell out of them, I was holding my hand at the time not a vice. Iím not sure if this was the case or not but perhaps it was.

I put the spheres back on with the use of a rubber mallet and reinstalled them back in the car. The rubber hoses to the accumulator valves and also to the pumps was looking tired so I decided to replace them. Iíd found information on the correct sizes and also that the hoses needed to be EPDM. Not fuel line. Interestingly one of the return lines from the accumulators on my car was fuel line and it didnít look or feel right. I found EPDM remote brake cylinder hose in the correct sizes and ordered them. When they arrived, they had a thin wall and werenít reinforced. My understanding is that the feed to the brake pumps is gravity only and the return from the accumulators is very low pressure so I figured they should be ok. They werenít, well not the ones for the accumulators. After putting everything back together, and filling the reservoir they leaked at the jubilee clips, no matter how tight they were. This was before the engine was even started.

In the end I ordered heater hose in the correct sizes, which wasnít simple to find. The hoses had EPDM on the side which was encouraging as the description said they werenít suitable for brake applications. The other advantage was they didnít leak.

Due to the delays in shipping parts and only being able to work on the car on weekend this process had taken a few months. The initial engine start-up was a bit daunting, I told myself I didnít care if it leaked, but I did. She fired up no problem and to my amazement, the brake lights went out, almost immediately. That canít be right considering everything Iíd pulled apart. Even more surprising was that nothing leaked, that definitely canít be right.

I had been using RR363 to refill the reservoir when I had the leaking issue but the cost and challenge of getting hold of two plus litres of the stuff didnít appeal. Mixing DOT 4 and castor oil has been well documented, and I figured it was time to give it a try. I went with 10% castor oil and Penrite DOT4. I suspect what I drained out wasnít RR363 anyway. Time will tell if it was the right decision or not.

Final step was to bleed the hydraulic system, which I wasnít looking forward to but in the end wasnít that bad. I ran the engine and bleed the accumulators, and front callipers. I sounds obvious but donít forget the front has two sets per wheel, I nearly did. Then the upper bleeder on the rears. My car has a master cylinder so the lower bleeder on the rear was a manual process. I used a hand vacuum pump which did the job, engine off. I lost pedal feel until the master cylinder was free of air in the system.

The height control system didnít make sense at first, I put extra weight into the boot, selected park, with the engine on opened the bleed valve but no fluid came out. I started to wonder if the height control had been deactivated, my car is early enough that it had been originally on the front. I wondered if the solenoid was the problem? I disconnected the rod from the height control valves and the body opened the bleed valve and with the engine running gently pushed the rod up. The side of the car lifted and at the same time fluid came out the bleeder! Same again for the other side. The passenger side didnít feel as smooth as the driverís side and took a little longer to return to normal height. I suspect that height control value will need an overhaul at some point but not today. System bled.

I did the work a few weeks ago and so far, so good, no fluid loss or issues. Before I did the work the brake lights would go out after a few seconds, now itís almost immediate. More encouraging is the system is holding pressure longer. The car sat for a few days and before it was started the brake lights didnít come on, I used the test button for the warning lights to make sure they were still working.

Iím glad I did the work in the end, but I wouldnít say itís an easy car to work on. I learnt a lot about the car, and itís given me confidence to address other issues that will no doubt come up. A regular brake flush isnít a daunting task anymore either. The job was a challenge the first time around but certainly achievable.
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Graham Phillips
Frequent User
Username: playtime

Post Number: 439
Registered: 03-2019
Posted on Tuesday, 19 October, 2021 - 15:20:   Edit PostDelete PostView Post/Check IP

G'day everyone,....


Congratulations and well done.

We still learn something new every day.

And it gives us a great sense of accomplishment.


Graham.
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Jim Walters
Frequent User
Username: jim_walters

Post Number: 350
Registered: 01-2014
Posted on Tuesday, 19 October, 2021 - 17:14:   Edit PostDelete PostView Post/Check IP

Did you remove the reservoir top and clean it out and check the filters for damage?

SRH8505 SRC18015 SRE22493 NAC-05370
www.bristolmotors.com
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Andrew Mclintock
New User
Username: amacka

Post Number: 2
Registered: 09-2021
Posted on Wednesday, 20 October, 2021 - 08:13:   Edit PostDelete PostView Post/Check IP

Hi Jim, I did clean out the reservoir. Fortunately it appears previous owners have looked after the car as it was clean. All the old fluid also looked clean as well as the bores in the accumulator valves. I was a bit worried they might need to be re-sleeved but they were good. The outer pump housings were the only area that looked questionable and as they were easy to replace I thought now was the time.
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 707
Registered: 11-2017
Posted on Wednesday, 20 October, 2021 - 08:48:   Edit PostDelete PostView Post/Check IP

Did you unscrew the actual screen filters located on the bottom of the tank? It is critical these are not breached. It's a micro-mesh screen and has a 1" hex on top.
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Jim Walters
Frequent User
Username: jim_walters

Post Number: 351
Registered: 01-2014
Posted on Wednesday, 20 October, 2021 - 09:58:   Edit PostDelete PostView Post/Check IP

Good that you cleaned out the reservoir too. I'm continually amazed at how seldom this is done, just last week another new customer brought his Shadow in with totally clogged filters. Someone else had been servicing the car for him but never thought to clean out the many years of accumulated muck in it, and wondered why he couldn't get any brake pressure out of the pumps.

SRH8505 SRC18015 SRE22493 NAC-05370
www.bristolmotors.com
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Andrew Mclintock
New User
Username: amacka

Post Number: 3
Registered: 09-2021
Posted on Thursday, 21 October, 2021 - 13:38:   Edit PostDelete PostView Post/Check IP

Thanks for the Advice Jim and Rob. I did check the filters and removed the baffle to check for sludge. I wasn't sure what I'd find when I started but it was better than expected. Motivation to keep up regular fluid changes as well.
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Andrew Mclintock
New User
Username: amacka

Post Number: 4
Registered: 09-2021
Posted on Thursday, 17 March, 2022 - 09:13:   Edit PostDelete PostView Post/Check IP

Itís been a few months since I did the work on the car and a couple of post repair issues came to light that might help others.

The first one wasnít too much of an issue, but annoying. The EPDM hose that I had bought to connect the fluid reservoir to the brake pumps had started to feel a little sticky. They looked fine but didnít feel right. The smaller diameter hose that was bought at the same time and used for the return line from the accumulator valves felt fine. Interestingly they had EPDM written on them, the others didnít but had been advertised as EPDM. In the end I found a suitable replacement and changed them over. That was a few months ago now and they still feel fine. I can only assume the first lot werenít EPDM.

The second issue was a little more elusive. Iíd done a few short drives in the car since completing the work, all without issue. Then one day coming back from a drive the right brake warning light came on, not ideal. I had visions of fluid leaking out or some other major issue, but nothing obvious. The brakes still felt fine as well. I thought maybe a broken rod on a brake pump (but really hoped it wasnít), I bleed both accumulators, expecting to find one with low pressure but they were both fine. All this time the right warning light remained steadily on. I little more research on the internet showed that people have had issues with the warning light switches on the accumulators.

I swapped them over and now both lights went out and behaved as expected. I hadnít fixed anything, but it was starting to look like a faulty switch was the issue. I found that if I repeatedly pressed the brake pedal (with the engine going) that one of the lights would come on and then go out intermittently. This time it was the left one, I was pretty confident that the switch was the problem.

I was able to get replacement diaphragms from Richard at Spur Parts and replacing them was straight forward. Comparing the two original diaphragms that come out, they were slightly different. I suspect one had already been replaced, why both hadnít been done, who knows. The switches went back in without issue and so far, everything is working as it should. I donít imagine the switches need to be done every time the accumulator values do but itís something to keep in mind. Other than changing the fluid, Iíd be quite content not spending any more time on the hydraulics for a while.
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Larry Kavanagh
Frequent User
Username: shadow_11

Post Number: 820
Registered: 05-2016
Posted on Thursday, 17 March, 2022 - 10:28:   Edit PostDelete PostView Post/Check IP

Nice work, enjoy the fruits of your labour. If you haven't already done so, I would suggest that you should remove the 2 restrictor valves for the height control and clean them and replace the seal on each. That's a routine service item which is often overlooked and the restrictor valves tend to become clogged.
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Andrew Mclintock
New User
Username: amacka

Post Number: 5
Registered: 09-2021
Posted on Thursday, 17 March, 2022 - 13:25:   Edit PostDelete PostView Post/Check IP

Larry, appreciate the advice. Other than bleeding and confirming it works I haven't done anything with the height control system. I still have a few things I'd like to do on the car, I'll add that to the list.

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