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1842 has at last come back to life, hurrah!
However, as it hasn't moved for over a year, I was expecting some brake issues.
I did remember to chock wheels and release handbrake, so at least they aren't frozen on.
Is there a recommended sequence of events I should follow in order to get pressure and flag to go up?
I was hoping to drive to workshop in order to remove front brakes for relining but can't risk as no sign of pressure building up .
Any one with nitrogen kit fancy a rural break?
;-)
My bus number (if any): 1842
The brake pump provides air for the brakes, accumulators are in case of an engine failure. Look at South Devon RM site, good information there about what does what and how to check brakes etc.
My bus number (if any): RTL 960, RMC 1458 RM 1585, M 961, M 271 and several RTs
A slight correction there Brian, the pump provides hydraulic pressure for the brakes. The accumulators provide a reserve of air pressure to take over in case the pump fails.
Are you sure the flag is not going up because the air for the gearbox isn't building up? listen for the load clonk of the cut-out valve on the accumulator operating, that'll give a clue.
My bus number (if any): RML2532 GS67 BEA MLL721 BEA MLL738 RT2629
Yes I was trying to differentiate between brake pump and accumulators, you can run with empty accumulators but the flag won't stay up. The different lights show if the problem is brake or gearbox won't they?
My bus number (if any): RTL 960, RMC 1458 RM 1585, M 961, M 271 and several RTs
Brian: Is it right the bus can still be driven safely with empty accumulators, the flag down and the light on? Obviously there is no safety back-up in these circumstances but I was always led to believe the only brake you have in these circumstances is the handbrake.
My bus number (if any): RM1001
When the flag comes down it reads STOP. What language does it need to be in to be understood?
Didn't say it was totally safe Mike, I said it could be driven, as long as the engine runs and why shouldn't it, the brakes will work.
We had to bring 1585 out of centre of Paris once with empty accumulators, flag kept dropping on idling but brakes worked fine. If the engine cuts out and accumulators are totally empty then as you say you only have the handbrake.
My bus number (if any): RTL 960, RMC 1458 RM 1585, M 961, M 271 and several RTs
If the belts break or the Plessey pump fail, no brakes except the handbrake!
STOP means what it says on the tin. Quite how you do it with no brakes is a moot point.
As a severe word of warning, I had a call about 5 weeks ago from a member on here whose bus ran out of brakes going down hill in Spain. the flag dropped, like it did 100s of times before,this time no brakes; downhill, snowing, approaching traffic lights, horn didn't work.. luckily he didn't collide with or kill anyone. I haven't heard back from him yet to fond out what the problem was, but it's very foolhardy to assume the brakes will work with the flag.
I also worked on an RM in Belgium 2 years ago, flag dropped sometimes, but even with the flag up, the brakes would sometimes not work! That was a defective pump, even though the accumulators were good and i was assured by the firm's resident fitter the pump was good, and that was after I'd fitted a new foot valve which he insisted was defective!
My bus number (if any): RML2532 GS67 BEA MLL721 BEA MLL738 RT2629
On closer inspection and a tentative drive round the farm,
Gearbox red light goes out but takes a while, white light isn't illuminated, there is no characteriatic clunk but there is some braking effect.
I am a little confused with my diagnosis. The south Devon site is a great resource, but doesn't quite answer it.. Accumulators (torpedo type) were replaced with new imperial ones maybe 4 years ago.
Flag has had a habit of dropping briefly, but returning straight away, over the years. I've never had the flag not go up at all.
Might the pump r be on the way out?
My bus number (if any): 1842
Far be it from me to suggest you that you spend some money, however it sounds as if you do not have anyone nearby who can recharge the accumulators. The simple answer is to purchase the kit to do it £350/400 and you can keep the accumulators charged and check them regularly instead of taking chances. The fact that your accumulators are only about 4 years old ( you haven't mentioned whether they have been recharged in that time ) means they probably just require recharging, then at least you can eliminate them from the problem if there is one elsewhere.
Standing still disease then.If the bus has been stood outdoors for the past year then it could have all sorts of problems. It has been most noticeable this winter how quickly evidence of lack of use has become apparent - even after only a few days.
You have to start somewhere so: does the white light work?
Thanks Ed..
After reading the South Devon website, I have resigned myself to buying the kit, then it will always be there just in case.
If I don't need to use it regularly, then that's ok too.
The last and only time these accumulator were charged was with Chris on a random industrial estate somewhere. Previously, I used to go to East Yorkshire Traction workshops in Hull where they had the intensifier kit and a really friendly driver's rest room...
The lesson to (re) learn for everybody, and especially me, is that these vehicles were designed for trundling about all day every day, not just for looking pretty in a field.
My bus number (if any): 1842
That's right, Roy.
Every Autumn I vow to go round the block once a week. This last year it didn't happen at all, hence the problem.
So, starting from where we are: white light doesn't illuminate at all, never has.
Might have done once when compressor drive belts snapped.
Wish I'd kept my vow to keep detailed and comprehensive log as well now....
My bus number (if any): 1842
First change the light bulb...either fit a new bulb or if the red bulb works, swap them over. The lenses unscrew, so in theory it's a simple task but never is if they've not been unscrewed for years!
Then post back here.
My bus number (if any): RML2532 GS67 BEA MLL721 BEA MLL738 RT2629
when you say the accumulators have been replaced by the the Imperial type, what do you mean by this? there are 3 types fitted; the Clayton type, large ball shaped (very rare to see these nowadays); the original type with screw-on ends, or the Titan type without screw-on ends. these always have a lump of rubber as a spacer where the clamps go.
My bus number (if any): RML2532 GS67 BEA MLL721 BEA MLL738 RT2629
The red bulb did work this morning
Swapped them over, surprisingly straight forward, now neither work :-(
Both bulbs now blown, no spares to hand...
My bus number (if any): 1842
Ed,
I'm all poised to splash out on nitrogen etc. but drawing a blank on the Shrader valve adapter.
I've followed several lines of enquiry, the latest response is that they are more common in France but can't be ordered singly!....
My bus number (if any): 1842
Hi, I got my one from a company called LAS Aerospace. It's called a Schrader high pressure strut coupler and comes up with the part number 556. I think they are around £30.
My bus number (if any): RM44. RM1138
Brilliant, Stuart!
I love the power of internet forums (fora?) Especially ROOF.
Ordered and on the way.
No surprise there's a connection with aerospace industry, given history of RM history and development...
My bus number (if any): 1842
Well I've had a break, changed brake pump and pulley for new ones I had kicking around, filled with grease, reconnected broken wires from the chocolate box connector, replaced the amusingly named warning bulbs and........
Eureka! Everything works fine in that red light went out after 20seconds, white one slightly after.
Flag dropped and light on after 5 brake pedal presses, staighy back up after revving engine...
Pedal still nearly goes straight to the floor, doesn't feel right.
I deduce that accumulaters require charging.
Will that improve the feedback through the pedal
At least I feel confident for the short a nd necessarily slow drive down farm tracks to neighbours barn so we can get really stuck in to removing front hubs...
My bus number (if any): 1842
Ian
You need to bleed the hydraulic system if you have disconnected the pipes from the brake pump when changing it. It will have to be a process of elimination while it is off the road, it will certainly help a great deal if the accumulators are fully charged. With the system charged the brake pedal should go down to the safety stop ( not the floor )and then require another approx 100lb of effort to bring the full accumulator pressure in for safety braking.
I am sure one of the experienced guys on here will tell you how they used to bleed the hydraulic side of the braking system. If the bus has been off the road for a long while it is essential to check that the brake cylinders at the wheels are operating efficiently and are not leaking oil.
Bleeding brakes! (no, not swearing...) Start engine, wedge "something" between the speedo box and the brake pedal, make sure the bus won't move by chocking the wheels, go underneath and open each bleed screw on the wheel cylinders in turn.
BEWARE- fluid will come out at high pressure and go everywhere. When fluid clear of bubbles comes out, tighten the bleed screw, go to the next wheel. continue process.
While the hubs are off, check the rollers on the brake shoes aren't siezed solid; you'll probably find the back ones are. If so, ome back for further advice!
