We have an 85 Coaster and in the wet it can be a bit scary trying to stop in a hurry as the rear brakes lock up, It even stalled the motor once and it wouldn't restart for about 5 min sitting at a set of lights in pouring rain.
Now I know it can be caused by contaminated brakes shoes (Drums on rear) either oil seal is leaking or brake fluid from wheel cylinder. I'm assuming here as to the cause as haven't pulled wheels off yet. Also can be caused by excessive brake dust in drums which I had this problem on a Jackaroo.
Now is any other Coaster owners 80's model that have similar problems, If so what was the cause. Tread on tyres is about 80/90% inflation is by specs. I seen a coaster on one of them videos taken by an in car cam and in the wet he was going sideways down the hill.
I usually do my own work but wondering what cost at brake place as it will be a PITA taking 4 wheels off then getting parts etc. Hope it is just brake dust.
Cheers Allan
deverall11 said
06:29 PM Feb 28, 2015
Sound like a brake bias inbalance. Too much rear brakes for the weight. If you had fluid leaking it would be the opposite - less brakes.
Larry
Mark Bolton said
06:32 PM Feb 28, 2015
FWIW fellow Coaster Clunker Owners ...
I have an 81 Coaster and like you my primary motivation is fear. Brakes / running gear / carreening off a cliff with none of the control inputs responding. Count me out.
The RHS Front was running hot when I got it. The wheel hub was looking cooked and discolored. I pulled off the wheel and it seemed that the brakes had been adjusted so they always dragged. Nothing complicated just it was always SNAFU. Backed the adjustment off a few clicks and now it rolls for ever.
Baffling. You really dont know what you are going to find.
I am reluctant to push a view or repudiate a theory blaming leaking brake fluid or billows of dust. I wont.
Machinery Faults are as you find them. It is too easy to anthropomorphise a simple mechanical failure and catch them up in a "whacckamole" "Tear my hairpiece to shreds" view of your supplier / support mechanic and trying to find fault and ascribe blame. "Cads and bounders that should never have been handed a spanner.!! By Golly."
I am a man of my generation and love the "Iv'e got a little list" cultural reference. Would that a broader philosophical view be at least countenanced? Perhaps some things on this planet are outside human control?
All this bull**** philosophy aside I am knocking this Coaster bus into some kinda shape ... YEAH!!
I hope I am not fooling myself as to my own competence.
Regards.
-- Edited by Mark Bolton on Saturday 28th of February 2015 06:55:06 PM
Jaahn said
06:58 PM Feb 28, 2015
Murraman wrote:
We have an 85 Coaster and in the wet it can be a bit scary trying to stop in a hurry as the rear brakes lock up, It even stalled the motor once and it wouldn't restart for about 5 min sitting at a set of lights in pouring rain.
Now I know it can be caused by contaminated brakes shoes (Drums on rear) either oil seal is leaking or brake fluid from wheel cylinder. I'm assuming here as to the cause as haven't pulled wheels off yet. Also can be caused by excessive brake dust in drums which I had this problem on a Jackaroo.
Now is any other Coaster owners 80's model that have similar problems, If so what was the cause. Tread on tyres is about 80/90% inflation is by specs. I seen a coaster on one of them videos taken by an in car cam and in the wet he was going sideways down the hill.
I usually do my own work but wondering what cost at brake place as it will be a PITA taking 4 wheels off then getting parts etc. Hope it is just brake dust.
Cheers Allan
Hi Murraman,
My suggestion is simple; take it to a brake shop NOW and get it fixed. What is an accident in the rain worth to avoid. I had a Coaster and a Civillian and an Isuzu, none had any difficulty locking up in the wet. I could give suggestions but if you do not know what to look for or check then get someone who does.
Jaahn
Murraman said
08:16 PM Feb 28, 2015
Jaahn, Thanks for your input, I do know what I'm doing as I have been repairing my own brakes for near on 50 years. Just wanted some feedback whether it was a common cause. My next step will be to remove wheels both sides to see what it looks like.
It has really good brakes in general but wet weather presents the problem, I just wish we had wet weather where I am as it is soo dry. On water restrictions and trees are shriveling up.
Deverall11, It has disc brakes up front, Drums rear. I'll check whether it has a bias valve. 85 maybe not but I'll check.
Mark keep at it, There will be a reward at the end.
Cheers Allan
exa41 said
08:32 PM Feb 28, 2015
Allan , I have a 83 coaster with front discs , I think from memory that your has front and rear drums ? It could be an adjustment problem or if it has had a reline , the front and rear shoes could have a different compound shoe , I know from the race car that different compounds have a totally different feel and operational qualities . I suggest give it a fluid change to make sure that the valving in the master cylinder hasn`t any crap in it preventing a full pedal stroke , just another thing to look at.
Mark Bolton said
09:39 PM Feb 28, 2015
Hi Allan, Thank you for your kind assurances despite the apocalyptic nature of the subject under discussion..
With old machinery there is always a temptation to over cook and over think the diagnostics. One scratches ones head, gives it a shakes and says "Nah ... couldnt be that stupid. .. It can and probably is" Just adjust it out ...
Murraman said
11:45 PM Feb 28, 2015
Thanks for your reply Dennis but how would you deduct that an 83 has discs and a later model has drums on the front. Ours is 85 and I can see the discs through the rims so it definitely has discs on the front and drums rear.
As I said I'll pull the rims and drums off the rear and have a look, Our nearest brake specialist is 100km away so I'll have a look first to see if any problem is evident and report back on here.
As i have said the brakes in the dry feel excellent, no pulling lockup or fading and stop real well. The brake fluid flush is a good idea as I have no idea when it was last done.
I did my Nissan Patrol recently and just opened up all the bleeders and made sure it didn't run out in the master, Took about 2 hrs and used about 1.5 ltr brake fluid. Easiest way to do it as others gave me that idea and it works a treat.
Cheers Allan
exa41 wrote:
Allan , I have a 83 coaster with front discs , I think from memory that your has front and rear drums ? It could be an adjustment problem or if it has had a reline , the front and rear shoes could have a different compound shoe , I know from the race car that different compounds have a totally different feel and operational qualities . I suggest give it a fluid change to make sure that the valving in the master cylinder hasn`t any crap in it preventing a full pedal stroke , just another thing to look at.
Aus-Kiwi said
01:18 AM Mar 1, 2015
Is there a load brake bias pressure switch in rear brake line ?
Check for play on wheel cylinder or pivot point.. If there's too much play or drum is warn ?
To excessively .. The leading shoe can jam, lock on... As they are self locking brakes compared to disc..
Which is what seems to be happening if shoes are dry...
Jaahn said
06:05 AM Mar 1, 2015
Hi Murraman, If you feel you can satisfactorily do the repair then I might suggest you get a repair manual. They are available on CD for a modest cost. Look on ebay.
I looked on my CD which is for later models and they clearly have a load proportioning valve on the rear system. I think I would be checking that it is in working order and someone has not disconnected or mis-adjusted the link settings. It cannot be correctly adjusted without some gear, so do not play with it.
The rear brakes may be manual adjustment type, in which case you should correctly adjust them first to see if that helps. If they are auto adjustment then adjustment is usually done by several hard stops in reverse until the pedal has stablised in height.
Each of the two cylinders on the rear, each side, in my experience has two pistons and one may sieze up so the shoes are not balanced properly as they wear. That affects even braking particularly if they are not adjusted properly.
As you said there may be excessive dust build up which needs to be removed. This will most likely be asbestos dust so I would caution you as to how you do this. Flushing the brake fluid is good but perhaps it is too late after 30 years.
Of course if there is any sign of fluid contamination that must be fixed. Either brake fluid which will be leaking cylinders or diff oil which is leaking axle seals. Either problem will cause more difficulties if there is a lot of dust buildup.
Not rocket science particularly if you have a workshop manual to assist. Jaahn
-- Edited by Jaahn on Sunday 1st of March 2015 06:12:37 AM
-- Edited by Jaahn on Sunday 1st of March 2015 06:18:49 AM
Old Col said
06:59 AM Mar 1, 2015
Murraman wrote:
. My next step will be to remove wheels both sides to see what it looks like.
Cheers Allan
on some Coasters rear drums you can not turn the adjuster backwards to release the brakes
you will stuff up the adjuster
there is a release lever through another slot which you have to hold, while backing of the adjuster (2 per wheel)
exa41 said
06:49 PM Mar 1, 2015
Sorrry I misread , thought it was an 80 model not an 80`S model.
mr glassies said
08:39 PM Mar 2, 2015
like someone said above take it to a break specialist . sorry but you put a post up here . to me you don't know about brakes so pay someone who does for your safety and others out there on our roads .
dibs
-- Edited by mr glassies on Monday 2nd of March 2015 08:40:13 PM
Murraman said
11:05 PM Mar 2, 2015
You mean brakes, As I said I was wondering if this type of vehicle had this sort of issue. Also I have spoken to a gent yesterday who had one and traveled in it for 10 years and he had the same problem and told me what causes it. That is the answer I was looking for.
And the answer is that ours like his is setup with very little weight over and behind the rear wheels, These were designed as a Bus to carry people (20) and the rear of our Bus has very little weight, It is all well forward of the rear wheels so under brakes the rear being lighter than it was designed to be, Which causes loss of traction. I didn't fit it out, We bought it as it is so you live and learn. The weight distribution cannot be changed due to the layout.
It sounds fair and reasonable to me, But I am still going to remove the rear wheels and have a look.
With all due respect, You may assume I know little because I asked but people who listen can learn, And I'm always learning.
Cheers Allan
mr glassies wrote:
like someone said above take it to a break specialist . sorry but you put a post up here . to me you don't know about brakes so pay someone who does for your safety and others out there on our roads .
dibs
-- Edited by mr glassies on Monday 2nd of March 2015 08:40:13 PM
blaze said
07:51 AM Mar 3, 2015
As a mechanic of too many years I would have to disagree with the reason given of loaded versus unloaded as that would mean it could not meet adr regs in the unloaded condition. The brake bias valve measures the movement of the chassis in relation to the rear wheels/axle to adjust the pressure available to the rear brakes, less braking is applied to the rear brakes in an unloaded condition
cheers
blaze
PS what you do with this info is upto you, its not my concern but rest assured just because someone had thee same problem for 10 years dosnt mean he has the right answer and the same goes for my advice. But please have a think about why vehicles have these devices engineered into them.
Murraman wrote:
You mean brakes, As I said I was wondering if this type of vehicle had this sort of issue. Also I have spoken to a gent yesterday who had one and traveled in it for 10 years and he had the same problem and told me what causes it. That is the answer I was looking for.
And the answer is that ours like his is setup with very little weight over and behind the rear wheels, These were designed as a Bus to carry people (20) and the rear of our Bus has very little weight, It is all well forward of the rear wheels so under brakes the rear being lighter than it was designed to be, Which causes loss of traction. I didn't fit it out, We bought it as it is so you live and learn. The weight distribution cannot be changed due to the layout.
It sounds fair and reasonable to me, But I am still going to remove the rear wheels and have a look.
With all due respect, You may assume I know little because I asked but people who listen can learn, And I'm always learning.
Cheers Allan
mr glassies wrote:
like someone said above take it to a break specialist . sorry but you put a post up here . to me you don't know about brakes so pay someone who does for your safety and others out there on our roads .
dibs
-- Edited by mr glassies on Monday 2nd of March 2015 08:40:13 PM
-- Edited by blaze on Tuesday 3rd of March 2015 08:03:38 AM
Jaahn said
11:08 AM Mar 3, 2015
blaze wrote:
As a mechanic of too many years I would have to disagree with the reason given of loaded versus unloaded as that would mean it could not meet adr regs in the unloaded condition. The brake bias valve measures the movement of the chassis in relation to the rear wheels/axle to adjust the pressure available to the rear brakes, less braking is applied to the rear brakes in an unloaded condition
cheers
blaze
PS what you do with this info is upto you, its not my concern but rest assured just because someone had thee same problem for 10 years dosnt mean he has the right answer and the same goes for my advice. But please have a think about why vehicles have these devices engineered into them.
Hi
I agree with these statements. If you think that the problem is about uneven loading then it follows that if the people in a bus only sat in the front seats then the braking would be dangerous in the wet. This is not correct and manufacturers actually know about loading and fit devices to compensate for it.
Having found another Coaster with the same problem means the two busses have the same fault. They both need fixing.
Jaahn
wasn_me said
05:13 PM Mar 3, 2015
Jaahn wrote:
blaze wrote:
As a mechanic of too many years I would have to disagree with the reason given of loaded versus unloaded as that would mean it could not meet adr regs in the unloaded condition. The brake bias valve measures the movement of the chassis in relation to the rear wheels/axle to adjust the pressure available to the rear brakes, less braking is applied to the rear brakes in an unloaded condition
cheers
blaze
PS what you do with this info is upto you, its not my concern but rest assured just because someone had thee same problem for 10 years dosnt mean he has the right answer and the same goes for my advice. But please have a think about why vehicles have these devices engineered into them.
Hi
I agree with these statements. If you think that the problem is about uneven loading then it follows that if the people in a bus only sat in the front seats then the braking would be dangerous in the wet. This is not correct and manufacturers actually know about loading and fit devices to compensate for it.
Having found another Coaster with the same problem means the two busses have the same fault. They both need fixing.
Jaahn
In another life I was a heavy equipment maintenance fitter with many qualifications. I agree totally with both attached quotes.
In Australia we have totally stuffed up laws. In some shires I could be heavily fined for changing a tap washer, because I'm not a licensed plumber,
But a busted arse farmer who has the local school bus run, can do what ever repairs he wants to the bus, himself, (including brakes) because you need no license to do mechanical repairs .
The same applies to that B double, grossing 62 ton, hurtling down the road towards you.
Cheers Pete
Murraman said
08:01 PM Mar 3, 2015
The way this bus is setup I have 18 people from 1 metre behind the door forward, the other gent added a lot of weight to the rear of his later on and never had another issue. I'll see what it looks like when the wheels are off.
Mine does not mention a bias valve anywhere in the manual, fixing brakes is not rocket science, drum brakes have been around since the beginning and are simple to fix if need be.
I have done hundreds of drum brake changes and never had an issue. They are all the same principle some are just bigger or smaller than others.
Cheers Allan
Aus-Kiwi said
11:15 PM Mar 6, 2015
Ahaha to brake experts !! Some are !
Jaahn said
11:52 AM Mar 8, 2015
Hi,
Perhaps enough has been said on the brakes by now.
If you feel the loading of the bus is causing the problem, after you have examined the brakes for correct operation, then the answer is really simple. Just the same as operating a truck, the driver has to arrange the load correctly for safe operation. I would put the bus over a weighbridge and see what the weight actually is on each axle. Then you may need to adjust the layout of the heavy item to achieve a balanced vehicle.
We have an 85 Coaster and in the wet it can be a bit scary trying to stop in a hurry as the rear brakes lock up, It even stalled the motor once and it wouldn't restart for about 5 min sitting at a set of lights in pouring rain.
Now I know it can be caused by contaminated brakes shoes (Drums on rear) either oil seal is leaking or brake fluid from wheel cylinder. I'm assuming here as to the cause as haven't pulled wheels off yet. Also can be caused by excessive brake dust in drums which I had this problem on a Jackaroo.
Now is any other Coaster owners 80's model that have similar problems, If so what was the cause. Tread on tyres is about 80/90% inflation is by specs. I seen a coaster on one of them videos taken by an in car cam and in the wet he was going sideways down the hill.
I usually do my own work but wondering what cost at brake place as it will be a PITA taking 4 wheels off then getting parts etc. Hope it is just brake dust.
Cheers Allan
Larry
FWIW fellow Coaster Clunker Owners ...
I have an 81 Coaster and like you my primary motivation is fear. Brakes / running gear / carreening off a cliff with none of the control inputs responding. Count me out.
The RHS Front was running hot when I got it. The wheel hub was looking cooked and discolored. I pulled off the wheel and it seemed that the brakes had been adjusted so they always dragged. Nothing complicated just it was always SNAFU. Backed the adjustment off a few clicks and now it rolls for ever.
Baffling. You really dont know what you are going to find.
I am reluctant to push a view or repudiate a theory blaming leaking brake fluid or billows of dust. I wont.
Machinery Faults are as you find them. It is too easy to anthropomorphise a simple mechanical failure and catch them up in a "whacckamole" "Tear my hairpiece to shreds" view of your supplier / support mechanic and trying to find fault and ascribe blame. "Cads and bounders that should never have been handed a spanner.!! By Golly."
I am a man of my generation and love the "Iv'e got a little list" cultural reference. Would that a broader philosophical view be at least countenanced? Perhaps some things on this planet are outside human control?
All this bull**** philosophy aside I am knocking this Coaster bus into some kinda shape ... YEAH!!
I hope I am not fooling myself as to my own competence.
Regards.
-- Edited by Mark Bolton on Saturday 28th of February 2015 06:55:06 PM
Hi Murraman,
My suggestion is simple; take it to a brake shop NOW and get it fixed. What is an accident in the rain worth to avoid. I had a Coaster and a Civillian and an Isuzu, none had any difficulty locking up in the wet. I could give suggestions but if you do not know what to look for or check then get someone who does.
Jaahn
It has really good brakes in general but wet weather presents the problem, I just wish we had wet weather where I am as it is soo dry. On water restrictions and trees are shriveling up.
Deverall11, It has disc brakes up front, Drums rear. I'll check whether it has a bias valve. 85 maybe not but I'll check.
Mark keep at it, There will be a reward at the end.
Cheers Allan
Hi Allan, Thank you for your kind assurances despite the apocalyptic nature of the subject under discussion..
With old machinery there is always a temptation to over cook and over think the diagnostics. One scratches ones head, gives it a shakes and says "Nah ... couldnt be that stupid. .. It can and probably is" Just adjust it out ...
Check for play on wheel cylinder or pivot point.. If there's too much play or drum is warn ?
To excessively .. The leading shoe can jam, lock on... As they are self locking brakes compared to disc..
Which is what seems to be happening if shoes are dry...
Hi Murraman,
If you feel you can satisfactorily do the repair then I might suggest you get a repair manual. They are available on CD for a modest cost. Look on ebay.
I looked on my CD which is for later models and they clearly have a load proportioning valve on the rear system. I think I would be checking that it is in working order and someone has not disconnected or mis-adjusted the link settings. It cannot be correctly adjusted without some gear, so do not play with it.
The rear brakes may be manual adjustment type, in which case you should correctly adjust them first to see if that helps. If they are auto adjustment then adjustment is usually done by several hard stops in reverse until the pedal has stablised in height.
Each of the two cylinders on the rear, each side, in my experience has two pistons and one may sieze up so the shoes are not balanced properly as they wear. That affects even braking particularly if they are not adjusted properly.
As you said there may be excessive dust build up which needs to be removed. This will most likely be asbestos dust so I would caution you as to how you do this. Flushing the brake fluid is good but perhaps it is too late after 30 years.
Of course if there is any sign of fluid contamination that must be fixed. Either brake fluid which will be leaking cylinders or diff oil which is leaking axle seals. Either problem will cause more difficulties if there is a lot of dust buildup.
Not rocket science particularly if you have a workshop manual to assist.
Jaahn
-- Edited by Jaahn on Sunday 1st of March 2015 06:12:37 AM
-- Edited by Jaahn on Sunday 1st of March 2015 06:18:49 AM
on some Coasters rear drums you can not turn the adjuster backwards to release the brakes
you will stuff up the adjuster
there is a release lever through another slot which you have to hold, while backing of the adjuster (2 per wheel)
Sorrry I misread , thought it was an 80 model not an 80`S model.
like someone said above take it to a break specialist . sorry but you put a post up here . to me you don't know about brakes so pay someone who does for your safety and others out there on our roads .
dibs
-- Edited by mr glassies on Monday 2nd of March 2015 08:40:13 PM
-- Edited by blaze on Tuesday 3rd of March 2015 08:03:38 AM
In another life I was a heavy equipment maintenance fitter with many qualifications. I agree totally with both attached quotes.
In Australia we have totally stuffed up laws. In some shires I could be heavily fined for changing a tap washer, because I'm not a licensed plumber,
But a busted arse farmer who has the local school bus run, can do what ever repairs he wants to the bus, himself, (including brakes) because you need no license to do mechanical repairs .
The same applies to that B double, grossing 62 ton, hurtling down the road towards you.
Cheers Pete
Mine does not mention a bias valve anywhere in the manual, fixing brakes is not rocket science, drum brakes have been around since the beginning and are simple to fix if need be.
I have done hundreds of drum brake changes and never had an issue. They are all the same principle some are just bigger or smaller than others.
Cheers Allan
Hi,
Perhaps enough has been said on the brakes by now.
If you feel the loading of the bus is causing the problem, after you have examined the brakes for correct operation, then the answer is really simple. Just the same as operating a truck, the driver has to arrange the load correctly for safe operation. I would put the bus over a weighbridge and see what the weight actually is on each axle. Then you may need to adjust the layout of the heavy item to achieve a balanced vehicle.
Jaahn