Post Number: 76
|Posted on Saturday, 12 April, 2014 - 10:54 pm: |
As you know, the master cylinder on the SS1 was deleted around August 1975. My SS is May 1975 and still has it fitted. I need to renew the rear calipers and I was thinking about fitting the later type of caliper and doing away with the master cylinder.
What would be involved in this conversion, and would it be worth doing? Would it actually be a retrograde step?
gordon le feuvre
Post Number: 30
|Posted on Sunday, 13 April, 2014 - 12:38 am: |
Having been involved with the Shadow since it's intro in 1965/66, I have always pondered this question. The problems we had in the early days were mostly about too much pedal travel before anything happened. This was combination of linkage problems, air in system AND too much clearance between pads and disc. This last one was/is exaserbated by rust/crud between pad disc which happens on cars that are little used and living habitat average rod speeds. Cars used on motorways always seemed to have good pedals. Over the years (late60/early70's)Crewe changed the linkage it seemed on a weekly basis, in the end deciding to adopt the spring instead of the master cylinder to give the necessary stop to actuate the pushrods into the distribution valves. What I am actually saying is that a SS1 with master cylinder, well maintained can be as good as later cars. Changing does take away originality. The easiest way is to get complete assembly off a scrapped car. I would think it would all "just fit" Even if you do this, still cover all bases by making sure reservoir is clean by taking top off (just sight glasses looking clean is not enough)To sum up ( excuse ramblings) Changing loses originality. Deletetion of m/cylinder gave the opportunity to get better brake pedal feel, the spring can be adjusted to suit personal preferences and got rid of the critical dependence of caliper/pad clearances etc and coutless hours trying to obtain a good feel to brakes by bleeding- over to you
gordon le feuvre
Post Number: 31
|Posted on Sunday, 13 April, 2014 - 02:12 am: |
Having thought some more, the basic problem was the master cylinder only has a limited supply of fluid to push down the line and push the caliper pistons/pads onto the disc. It is very unnerving to have to double pump the master cylinder to get more fluid through as well as being a very un Rolls-Royce experience. With the change to the spring/mechanical on stop, the situation was controlled in as much as thing will always be the same and so the pedal "feel" will remain constant. Very re-assuring for the driver of ANY car. As the only fluid now passing to the calipers is accumulator/high pressure, the fact that rust etc. on the caliper holds the pads off is not critical as the flow of fluid/pressure of of a much greater volume. Given the problems of obtaining the later system and fitting same, I hope I have given you some direction. \given this , I have a '73 Corniche that I am quite happy with the brake feel as standard!
Post Number: 379
|Posted on Sunday, 13 April, 2014 - 03:04 am: |
A factor you should consider is whether this proposed modification to the brakes requires that you inform your insurance company of the changes. If so, I suspect that what is a minor and perfectly safe modification to us on this forum may start alarm bells ringing with your local insurance agent, who is highly unlikely to be familiar with Silver Shadow braking systems.
I purchased a hand operated vacuum pump for about 30 bucks to bleed the master cylinder on my SY1 and have always had good "feel" with the brakes.
I think this really is a case of what you prefer. In my case, I'm quite happy with the SY1 system.
Post Number: 380
|Posted on Sunday, 13 April, 2014 - 03:27 am: |
As an afterthought, do you realise you will have to replace the rat-trap also.
Post Number: 77
|Posted on Monday, 14 April, 2014 - 01:26 am: |
Thank you for your responses. I assume (rightly or wrongly) that a Shadow 2 rat-trap would fit.
I am not bothered about originality if it is an improvement on the original. I would rather "Take the best there is and make it better", to coin a well-known phrase.
Post Number: 3015
|Posted on Tuesday, 15 April, 2014 - 10:45 pm: |
Rather than gas the place, I like to roll my T-Series out of the garage and stop it gently on the driveway before starting it cold after a week or two. Very safe as it has a master cylinder. When I first had my Turbo R, I did the same in the Swiss Alps just once and literally almost dropped off a precipice as I momentarily forgot that there are no brakes after a week or so parked without a master cylinder. Easy you say, apply the parking brake or select Park, but the surprise factor was alarming.
The same would happen with a late SY or any SZ after a few hours were the accumulator spheres depleted or the valve bodies imperfect as many unfortunately are.
At least the master cylinder applies pressure on demand. The other systems only provide pressure if the engine has been run sometime not too long ago, and even then assuming that the hydraulic systems have more than a few brake pumps' capacity left.
All these brake systems are rather splendid, but the redundancy diminished from 1975. Early SYs have three independent systems with at least two applied to each wheel. Later SZs and early SZs have two independent systems with two systems applied to each wheel. ABS cars have two systems with just one applied to each AXLE.
Perhaps taking the best there is and making it better on an early SY simply means a quality overhaul without tinkering.
Post Number: 381
|Posted on Wednesday, 16 April, 2014 - 12:48 am: |
I agree with Richard. It is quite useful having the additional braking circuit. Also a quality overhaul without tinkering would be the way I'd go.
In answer to Bob's original questions, and this is purely my personal opinion:
Would it actually be a retrograde step?
Probably not, but the improvement to "feel" and perhaps braking efficiency are not going to be that great. I've always found the brake system to be perfectly adequate on my SY1. After all, this is not a performance vehicle. As mentioned above, it is quite useful having the additional braking circuit.
would it be worth doing?
I originally thought this would be an easy modification, however when you consider the difficulty of changing an SY1 rat-trap with one from an SY2 I suspect this would be a quite major amount of work for very little improvement in the braking system. I very much doubt the many brake pipes that connect to the various components on the SY1 rat-trap will match up to the SY2 one, so there will be the requirement to re-route a lot of the pipes which will by now be quite brittle. In my view, this job has the potential to turn into an absolute nightmare, for very little gain.
Having said all this, if you do decide to go ahead it would certainly make for an interesting thread on this forum.
Post Number: 215
|Posted on Wednesday, 16 April, 2014 - 11:55 am: |
Seems to me the master cylinder circuit is dirt-simple: a good master cylinder, good calipers, plenty of clean fluid and no air, and you're good to go. Why mess with a good thing?
You gotta remember: these Cars are OLD in car-years, so you need to go deep and fix everything, get everything back up to snuff if you want good performance. They will do a very nice job if put and kept in good condition. Just my opinion, of course.
richard george yeaman
Post Number: 156
|Posted on Wednesday, 16 April, 2014 - 06:49 pm: |
I think Richard Geoff and Randy have summed it up very well having that small master cylinder in reserve is so reassuring !!!!
Post Number: 102
|Posted on Wednesday, 16 April, 2014 - 07:15 pm: |
Hi Bob, I replaced the brake fluid in my Shadow in last few days. I had problems bleeding the system in the past so I put a bleed screw on the master cylinder to ensure it is working correctly(naturaly I removed same and reconnected line). I did same as I resealed the master cylinder a few years ago but could get no low pressure pedal, it was isolated back to master cylinder by using the bleed screw, thus meaning I had to reseal it again.
Post Number: 539
|Posted on Wednesday, 16 April, 2014 - 09:38 pm: |
I would be loath to mess about with a braking system that worked on cars of our type. Despite their age they are still more than capable of exceeding 100MPH (160KPH) and with over 2 tonnes of rest mass to 'add insult to injury' that is a sh*t load of energy to wipe off before becoming part of the scenery rather than looking at it!
Our US colonials have got it right (for a change) with the phrase "If it ain't broke, don't fix it".
Post Number: 1185
|Posted on Thursday, 17 April, 2014 - 05:11 am: |
Argh I hate this sites 'preview and submit' buttons. lost my more lengthy reply . . .
There is no need to change the whole mechanism if going from a master cylinder to non master cylinder set up.
To get the best pedal feel but also better bleeding and back up brakes, then fit a master cylinder with a slightly larger bore size. Land-Rover MkI I think. Same casing, slightly bigger internals.
When you bleed, clamp one side and bleed the other side, swap clamp to the other side and bleed the opposite one.
The feed to that master cylinder is far higher up in the reservoir - so when you bleed it is imperative that the fluid level is kept to max. The master cylinder will run out of fluid way before the high pressure system does. Many people have come a cropper over this.
Make sure the master cylinder on stop is in good condition (or fit a solid metal one off a later car instead). The early ones have a rubber metal sandwich that delaminates. Cross Drill and bolt it if falling apart.
If that doesn't make sense when you are looking at it, come back and I'll see if I can find a photo.
Post Number: 1378
|Posted on Thursday, 17 April, 2014 - 08:02 am: |
I hate the preview and submit facility as well but it is a common feature on many forums; I have learnt from bitter experience on other forums subject to time-out limits [and mistakes on my part by not following up by using the "send" button before returning to the list of posts] to highlight all the text and click on "copy" before hitting the preview and send button.
This allows you to start again by pasting the original text into a new post and making sure you hit the send button and confirming the message appears on the forum. For long and complicated responses, I open my word processor, compose the message and then copy it across to the forum making sure it is posted before deleting the word processor version; saves a lot of time and angst when things do not go the way they should.....