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Re [Brake calipers]

G

Guest

Guest
Hi Renate
Correct me if im wrong and I may be but if you have a problem with the
calipers do you not just get new pistons (dont know what they are really
called. Is this not the case because the calipers are mainly just the one
piece of metal with the pistons in there to push against the pads. Geese
that is a lot of money to spend for those little things. You have the 91,
what month was it made, have you ever thought of any other braking mods or
things for better braking etc. I am looking at new something or other for
mine because I feel a little tiny catch when I nearly come to a stop which
gives me the idea that I may have a bump or something on one or more of my
discs. I would reakon that my bits for the brakes are there from the time
zero if all the other bits are any thing to go by but ?500 for two WOW O
WOW. I have heard that it is possible to get more braking power from better
rotors and ceramic pads but I would like to have more surface area of pad at
rotor, at learst that was the idea to maybe get new bigger calipers and new
better rotors and pads but if the ?500 is for calipers only, I think ill do
something else. Do you know of any places in the UK that do slotted rotors.
I found a place in AUS DBA rotors that are supossed to be very good buy they
weight 25 lbs each and as such I can only not think about the shipping.
Congrats on the new job wish you all the very best.
John C
92HDJ 80 1HDT Ireland
----- Original Message -----
From: <[Email address removed]>
To: <[Email address removed]>
Sent: Wednesday, July 06, 2005 8:21 AM
Subject: [ELCO] Re [Brake calipers]
 
Hi All
Renate/John B. I would be putting most of my money on improving the quality
of the brake pads for the front discs as I believe that the bulk of the
initial braking force goes to the front wheels and as most of the weight of
the car is towards the front (engine, me, socket set under seat, assorted
spares in middle compartment) it would make sense. I guess you can lock
your wheels at low speed but (when the ABS is working properly) I don't
think I have ever been able to fully lock the wheels my TLC? Not so that
they would smoke anyway.
I know there are performance pads available for other cars so I guess it is
worth doing a search. I still rely on the engine slowing down my ol Beastie
unless I have completely mis judged a situation and then hammer the brakes
and cross fingers!!!!! Can you imagine the forces the discs are dealing
with trying to stop a loaded TLC at 70 mph???
Regards
Simon Hughes
Principal Consultant
Tel: +44 (0) 207 2504710
Mob: +44 (0) 7973 288061
E-Mail: [Email address removed]
Website: www.marshallwarburton.co.uk
Disclaimer: The information contained in this message is intended only for
the recipient, may be privileged and confidential and protected from
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Hi Renate,
Actually most of the braking work is done on the front brakes which is
why the pads are larger!
One of the key things with all these seizing calipers is to make sure
that the fluid gets flushed regularly, usually when I change the pads,
and that you check the visible rubber seals when ever you change the
pads.
I keep a set of severely worn pads to hand so that I can full extend
the pistons in the calipers to inspect the rubber seals.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
Renate
| At one time I thought it was the front brakes that are the more powerful ones; the
| pads are larger, but the back pads are smaller but the rear discs are
| considerably larger than the front ones. When I brake hard the wheels have smoked
| at the back, so I guess the back braking is the more dedicated one.
I don't think is so.
When you brake the force stopping you (brakes) is at axle level, but the centre of gravity (engine, body, you, etc) of the truck is higher up. So the car tries to rotate forwards (nose dive) putting more downwards force on the front wheels, and correspondingly less on the back wheels.
This means that it is easier for the back wheels to lock up and skid, as there is less pressure holding them to the road, and probably explains why you see those smoking first. (If you think back to your bicycle riding days the same applies: it is easy to skid the back wheel with the brakes, or even lift if off the ground, but much harder to skid the front.)
Most cars have a load sensing brake pressure reduction valve for the rear brakes that senses the height of rear axle, and hence the weight on it, and restricts the brake pressure to the rear as the axle rises. The idea is to stop the rear wheels locking up and causing a skid, although if ABS is fitted the skid will be minimised anyway.
Christopher Bell
 
Something else to add on the issue of calipers.
In my experience most garages will always opt to go for new calipers
because they cannot be bothered/don't have the experience to replace
the seals on the calipers.
A seal kit is peanuts from Milners and it is not too difficult to
change them - the big problem with them is whether the pistons have
become corroded due to water or other contaminants in the brake fluid
(in my experience it isn't often that the actual caliper housing
corrodes).
If the pistons have been severely corroded then it should still be
cheaper to replace the pistons.
Thinking further, I can actually understand why a garage will prefer to
just swap out the calipers, because it may actually work out cheaper
than them stripping down and doing the seals at the hourly rates they
charge.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
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Re [Brake calipers](chat)

Hey Simon
Would you stop with all that imagine at 70 mph etc. I think of things like
this all the time. All the little bolts or nuts , pipes, hoses, basically
all the bits that could kill you if they failed including a tyre blow out,
you would never hold it on the road and it would turn over for sure. Now see
what i have gone and done, Im going to take some strong medication to calm
down now. Now I know I want better braking and a roll cage and punchure
proof tyres and and and and and I think ill just walk everywhere. Any one
want to buy a cruiser. HAH not a hope so get that out of your minds never
never. Thought you had cracked me well not yet if I can put up with me than
I can put up with a bit.
John C
92HDJ 80 1HDT Ireland
----- Original Message -----
From: "Simon Hughes" <[Email address removed]>
To: <[Email address removed]>
Sent: Wednesday, July 06, 2005 9:46 AM
Subject: RE: [ELCO] Re [Brake calipers]
 
Hi Julian
When you say one should change out the brake fluid often what do you mean ,
and yes here it comes how do you do it, or should I say how does a prat like
me do it and expect to have brakes afterwards or should I forget about it
and let others do it.
John C
92HDJ 80 1HDT Ireland
 
On 7/6/05, Christopher Bell <[Email address removed]> wrote:

brakes that senses the height of rear axle, and hence the weight on it, and restricts the brake pressure to the rear as the axle rises. The idea is to stop the rear wheels locking up and causing a skid, although if ABS is fitted the skid will be minimised anyway.
As Christopher says, have you thought of checking the brake
proportioning valve (i.e. if it's there)?. That valve is just as
important as the quality of disks/pads.
--
Rgds,
Roman (London, UK)
'92 HDJ80
 
Hi John,
I assume that you understand that the brakes are operated hydraulically, at
a simplistic when you press on the brake pedal it moves a piston in the
Master cylinder that forces brake fluid down to the calipers which in turn
contains pistons (slave cylinders) that force the pads onto the disks.
The brake fluid is designed to lubricate the pistons and is also designed
to be difficult to compress, however over time it deteriorates and the
deterioration can accelerate if air or water gets into the system or the
calipers over heat, etc.
To flush the fluid, you do exactly the same as you would do to bleed the
brakes, but pump through a lot more fluid.
Take the wheels off (you don't have to, but it saves having to crawl
underneath on your back), top up the reservoir with new fluid and then
start at one corner and whilst someone presses down on the brake pedal open
the bleed valve and let the brake fluid flow out into a container via a
clear tube on the valve, only keeping the vale open whilst the pedal is
depressed and the fluid is flowing - as soon as it slows, shut off the
valve and get the pedal released and re-depressed. It is advisable to pump
the pedal a couple of times initially to clear any vacuum from the brake
booster before starting.
The order to do the corners is:
Rear Right
Front Left
Rear Left
Front Right
Load sensing proportioning valve.
On the first corner you will need to do this several times to get the old
fluid out of the main lines. Usually the brake fluid gets darker over
time, so you keep repeating the routine until clearer and lighter fluid is
pouring out, then move onto the next corner.
If you are on your own you can use a brake bleeding kit to make it easier.
I usually use a pressure system where you have a pressurised container of
fluid plumbed into the reservoir and then just go round each corner opening
it up until it runs clear however LC reservoirs have clip on caps so it is
harder to make a seal.
Alternatively, you can get some tubes with valves in them so that all you
have to do is connect the tube to the bleed valve, open the valve and then
pump away until you have clear fluid flowing.
At all times make sure you have enough fluid in the reservoir, it doesn't
take long to empty and once air is in the system you have to pump through a
lot more fluid to clear it.
Also if you are using a pressure system, it is still worth opening up a
corner and pumping the pedal a couple of times, to make sure the fluid in
the master cylinder is replaced - usually safest to do it when you are
doing the front driver side.
And with the LC you will need to flush/bleed the brake proportioning valve
that is above the rear axle, designed to adjust the balance of the braking
front and rear depending on the weight on the rear axle.
It's pretty straight forward and I am sure you should have no problems
doing it.
It does make it easier if you have four axle stands so you can take all
four wheels off or a ramp.
A day or so before you do it, it is worth using a wire brush to clean of
the bleeding valves and giving them a good dose of WD40 and when you first
open them try to use either a tight fitting socket or ring spanner, because
it doesn't take much to either snap them off or rounding the flats.
Sorry, a bit verbose, but should cover most bases.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
Hi Julian
Brilliant write up and I have ordered the Power Bleeder from Sealey, a
couple of hose clamps and an adapter for the clip on clamp which after
ordering I realised my 80 has a screw on cap. Duhhhhh.
Regards
Simon Hughes
Principal Consultant
Tel: +44 (0) 207 2504710
Mob: +44 (0) 7973 288061
E-Mail: [Email address removed]
Website: www.marshallwarburton.co.uk
Disclaimer: The information contained in this message is intended only for
the recipient, may be privileged and confidential and protected from
disclosure. If the reader of this message is not the intended recipient, or
an employee or agent responsible for delivering this message to the intended
recipient, please be aware that any dissemination or copying of this
communication is strictly prohibited. If you have received this
communication in error, please immediately notify us by replying to the
message and deleting it from your computer.
 
Hi Simon,
Thanks.
I've always used Gunsons cheepo Eazi Bleed system, although looking at
the powerbleeder system I might just go and get the adaptor and use one
of those small garden hand pump sprayers you can pick up for a few quid.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
Hi Julian
Shame we don't all live nearer to each other as all this kit we keep buying
could be shared out around the forum. I mean how often do you change wheel
bearings and bleed brakes?????? Don't answer! Once every 5 years is enough
for me.
Regards
Simon Hughes
K reg TLC 4.2l TD 156k
 
Hi All
Used the Power Bleeder from Sealey this weekend and it proved to be money
well spent. Julian was right as the pump does come with a screw on cap but
guess what its too small so luckily I had ordered the extra adapter that
bolts onto the top of the reservoir. Put a litre of brake fluid in the pump
pressurised to 10 and then started bleeding each wheel in the order Julian
suggested. Initially the fluid was dark golden color but started to run
clear after a minute so onto the next rear wheel. This one was good as bits
of rust and metal came out and then ran clear. Off to the passenger front
and now it got interesting, black thick glop came out with lots of air as
well took ages to run clear. Drivers side same color less air so all in
including jacking up and down and pulling wheels 1 1/2 hrs?? I then crawled
under the back and tried to bleed the LSPV but the nipple opens and nothing
comes out? Fluid does leack past the nipple threads though so I let that
run for a bit . Will have to replace the nipple later. Notice the brake
pipes are corroding with white powder and quite a bit of rust evident. Also
rear exhaust is rotted thru near the spare tire so will have to sort that
out for the MOT.
Used nearly a litre replacing the brake fluid so I think it must be all
purged now. So all I have to do is replace drivers side bearings, fix
exhaust resolve the ABS light, bleed clutch, pull rear hubs and grease, etc
Regards
Simon Hughes
K reg TLC 4.2l TD 156k
 
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