Hot Brakes: Causes and Solutions

Hi there!
Seat Terra, year 1992. No ABS, no other features, so a very basic diesel car from the Stone Age.
After applying the brakes, the front disc brake becomes hot.
I disassembled the brake cylinders and everything else, but I didn't find anything wrong.
The main suspect is now the brake cylinder or its pressure relief valve.
However, at that time, a different brake booster was installed instead.
Can I rule out the brake booster, or could it be too large, too powerful, or something else?
Best regards, Frank.

It can't be a problem with the main brake valve itself, because if it were, all the brakes would be squealing. So, there must be something wrong with the caliper. Are you sure it's clean, do you have new seals, and are the brake pads installed correctly? If everything is in order, then you probably need to replace the entire caliper.

If all of that is the case, you will need to replace the brake caliper.

Hi Matthias,
Are you actually referring to the brake caliper and not the master cylinder?
Best regards, Frank.

Okay, so...
the description:

After applying the brakes, the front disc brake becomes hot.

It sounds a bit strange since the brakes generally get hot when you're braking.
Friction generates heat.

Is one brake getting significantly hotter than the other?
Are the brake pads moving freely in their holders? (verschandeln them with sandpaper and apply copper grease.)

Is the piston seal in the brake caliper 100% intact? Because it's what retracts the piston.

Is the piston moving freely and free from corrosion?

Regards,
Hinrich.

So,
the description:

After applying the brakes, the front disc brake becomes hot.

It sounds a bit strange since the brakes generally get hot when you're braking.
Friction generates heat.

Hi Hinrich,
I'm sorry, I thought it was clear.
Hot because it's solid.
The question wasn't about what was causing it, but whether I could rule out the BKV (Swiss basic health insurance).
I can do that now.
The pistons can be easily pushed back, but only if the bleed valve is open.
According to the report, the relief well in the hazardous waste disposal site is sealed.
Can it be freed by disassembling and cleaning? Or is a replacement of the hotend necessary?
Best regards, Frank.

I wouldn't rule out the brake booster in your situation.
especially if a different one was installed before. If the length of the transmission...
'The distance between the brake pedal and the main brake cylinder in the BKV (likely referring to a specific vehicle or system) is too large.'
Is it possible that it feels like the pedal is being lightly pressed constantly?
You could try testing the following:
Press the brake pedal and release it. Are the brakes then firmly engaged again?
Loosen the master cylinder (possibly remove the nuts completely!), and then remove the cylinder.
pull forward - then, if the brakes release, you've already got some momentum.
Note: I'm not familiar with the BKV system in your car, but it existed in the past.
Examples where the adjustment rod was adjustable.

Warning! Do not forget to securely tighten the main brake cylinder mounting bracket!

Sure, here's the translation:

'One more question:'

Are both front brake calipers stuck, or just one side?
If both sides are fixed, I would also suspect a faulty BKV (Brake Control Unit).

HBZ is actually very unlikely.

If only one side isn't working, I would check the brake hoses. They can swell internally, or rubber pieces can detach, which can then block the hose, for example, when braking or releasing a valve.

How old are the sausages?

HBZ is actually very unlikely.

Hi there!
Alternatively, the balancing borehole may be completely or partially obscured by an excessively long control rod.
I'll test what Jürgen said later.
Best regards, Frank.

Hello FB (By the way, that's also the beginning of my car license plate!)

I'd be interested to know how things developed further.

I had a similar case a few years ago with the...
Motorcycle. After an accident where I fell over, the brake lever hit something.
replaced with a replica from Louis, where the camshaft was slightly too long.
was. It wasn't immediately noticeable after installation; it only became apparent after about...
The motorcycle started to respond poorly to the throttle after 120 km and it became increasingly...
slower. The front wheel brakes were hot. Brake lever came loose during the ride.
expanded and the cam was ground down on the concrete curb until...
It was working again!

That's already possible with motorcycles.

However, if this condition were to occur in a passenger car, all four brakes would likely be locked up because it would not be possible to release the pressure due to the closed openings.

Hello Golfschrauber1981,

Sorry if I disagree with you. Your argument would be valid in a...
Single-circuit braking system (My good old Peugeot 404 from 1967, which I...).
'He drove that car for a decade, may God bless him, he really loved it!' - conclusive.
In a dual-circuit braking system, such as the one described here, it is quite possible that...
that the balancing borehole in a certain area is still available, while the second one...
The area is already blocked. We're talking about extremely tight tolerances here, especially...
here, relatively flexible cuffs also come into play, and the pistons in the...
Main brake cylinder with springs applied. Also, it could be that...
The design of the combined brake system can also cause a delay in the rear braking circuit.
is being commissioned. The process could be affected by the tight tolerances in the...
'Also, the brake squeal is getting worse, it's like it's being amplified with each braking event.'
will be. Also, it seems that in the case of FB models, the front disc brakes are not fully...
'It doesn't completely block it, but only partially. I can't imagine that...'
It is still possible to drive with front wheel brakes that are completely blocked, without using the clutch.
smoking!

Always remember: You've seen things you shouldn't have, and sometimes right in the middle of everything.
in front of the pharmacy!

'Yes, but even if that's the case, due to the diagonal brake split, there should also be a problem with the rear brakes. I assume there are drum brakes on the rear, which would at least get warm (and quite hot, thanks to self-amplification and poor heat dissipation).'


Furthermore, it could be that...
The design of the combined brake system can also cause a delay in the rear braking circuit.
is commissioned

This would have resulted in uneven braking.

Or am I making a mistake in my thinking?

For the BMW E30 (BJ 92) without ABS, a load-dependent brake force regulator could be used for the rear axle.
A speed limiter that is independent of the vehicle's last used setting may be installed. If the vehicle then has a very...
It's easy, especially when you're traveling alone a lot, for things to not quite connect in the back.
I remember some vehicles where you had to bleed the rear axle...
'Had to disengage the brake force distribution system and apply the brakes directly – otherwise, nothing would have worked!'
Ich bin mir auch nicht sicher ob Diagonalverteilung allgemeiner Standard war. I think.
Probably not. Some manufacturers advertised that their cars had this feature back in the 80s (I think I'm getting old!).

What made me particularly curious was the change in the BKV (a Swiss health insurance system).

But maybe F.B. will tell us what kind of error he found at the end.

Hello,

Sure, here's the translation:

"Two more points to consider:"
- Brake caliper pistons may be seized due to a leaky rubber boot (you probably already checked this).
- Brake caliper pistons installed incorrectly (twisted). Some pistons do not have a completely round contact surface on the brake pad carrier; instead, approximately 90 degrees of the cross-section are "missing". It's best to compare it with the side that is working correctly.

Best regards, Rainer.

But maybe F.B. will tell us what kind of error he found at the end.

Hi Jürgen,
A trailer coupling valve is available.

Right now, I can't get into the garage, and because of the heavy rain (terrible weather), I don't want to work outside.
I'll let you know what I found.
The thing about the excessively long control rod of the BKV sounds very logical and fits the timeline!
Let's see when the rain stops.
Best regards, Frank.

@ Frank,

Good luck - if the adjustment rod in the BKV is too long and not adjustable.
Perhaps you could do something on the pedal side in the footwell. That's actually...
A continuous rod that runs from the pedal to the rear brake, connecting only in the middle.
des BKV durch die Membran geführt und an dieser befestigt ist. The membrane does...
basically, they only need to provide support for this rod, which is sufficient to handle the pressure difference.
between the atmosphere and a vacuum created by the vacuum pump (diesel).
or utilizes the intake manifold (carburetor).

@golfschrauber1981

Many older vehicles only had a single brake line to the rear axle, where it...
then it was distributed across the pages. A diagonal distribution is then not possible.