Naninikit na brakes

[PamelaAsistio]

Hello tsikoteers, just wanna have some accurate advices po sana. More than a week ago, tumirik po ang car ko and I smell something na nasusunog na goma. I checked all the tires only to find out that my 2 front mags are hot kaya pala ayaw umandar dahil sa paninikit ng brakes, so I called a nearby mechanic and told me that my caliper brakes need to overhaul.
To make the long story short, dinala po namin yung car sa shop nila at kinalas mga caliper brakes, niliha at konting linis ang ginawa then they charged me for 600 labor.
So after a day, maayos sa umpisa ang brakes pero pag matagal ng ginagamit ay tumitigas po ang brake pedal at mejo nangangamoy uli ang preno. Binalik ko uli sa kanila at nilinisan lang uli un mga brakes at sabi ay okey na daw. But just recently ay nangyari na naman po ang same scenario...Im sick and tired of this na pabalik balik po ako sa shop at abala sa oras. I just want to have enlightenment kung ano po kaya ang sira ng car. Sabi nung chief mechanic ay baka daw busted na yung piston pero sabi naman po nung gumagawa ay maayos daw yung piston at linis lang ang kelangan...kaso ay paulit ulit na lang pong nangyayari eh. Very reliable po ang car ko kahit pa may kalumaan na at nagagamit ko kahit saang long drives..pero lately hinde po ako panatag sa auto, kahit mag-grocery lang ako, 2 blocks away from ours ay nangangamba akong manikit na naman ang preno (which again happened yesterday).

Ano po kaya ang real culprit at permanent solution about my brake problem? Gusto ko po kasi masolusyonan ito ng tama at hinde ko naman po madala sa ibang shop dahil sayang naman po binayaran kong labor sa kanila na hinde pa naman nila totally naayos.
By the way, my ride is nissan 86

Sorry po if medyo mahaba ang queries ko. TIA )

[yapoy86]

its a clear case of a busted hydro-vacuum assist.. replace your hydro-vac asap

[PamelaAsistio]

its a clear case of a busted hydro-vacuum assist.. replace your hydro-vac asap

Sir yapoy, hydrovac po ba ang problem kahit na yung brake at mags sa front right side lang ang umiinit at madalas umiipit ang preno? Actually, both front brakes and mags ang umiinit, but only the right side is drastically hotter, hinde po mahahawakan in bear hands dahil siguradong mapapaso...while the front left side ay halos maligamgam lang naman

[yapoy86]

malamang sa malamang hydrovac ang problem kasi sabi ok naman ang caliper mo

[t2erns]

the brake booster or hydrovac (tawag ng iba) is there only para mag assist sa tapak sa pedal (thus it's called brake booster). one side of that big cylinder is vac and the other side is atmospheric pressure. so walang kinalaman sa pag stuck up ng brake (pwera na lang kung masyado mahaba ang pushrod at nakatulak agad sa master cylinder (not common).
from your kwento parang nililinis lang nila at hindi pinapalitan ng caliper overhauling kit kaya pabalik balik ang paninikit ng preno. since medyo me edad na yung car maaring sira na rin ang internal ng brake hose kung baga steel braided ito meron na mga himulmol yun sa loob at hindi na nakakabalik ang fluid pag bitaw sa pedal.

[PamelaAsistio]

the brake booster or hydrovac (tawag ng iba) is there only para mag assist sa tapak sa pedal (thus it's called brake booster). one side of that big cylinder is vac and the other side is atmospheric pressure. so walang kinalaman sa pag stuck up ng brake (pwera na lang kung masyado mahaba ang pushrod at nakatulak agad sa master cylinder (not common).
from your kwento parang nililinis lang nila at hindi pinapalitan ng caliper overhauling kit kaya pabalik balik ang paninikit ng preno. since medyo me edad na yung car maaring sira na rin ang internal ng brake hose kung baga steel braided ito meron na mga himulmol yun sa loob at hindi na nakakabalik ang fluid pag bitaw sa pedal.

Sir t2erns, in my understanding from what you have said...pagbalik ko po sa shop I should suggest the followings:
- palitan ang piston ng caliper (I think, ito ata yung rubber thing na pinakita sa akin ng mechanic)
- check / clean the brake hose

Hinde din po kasi nababanggit ng chief mechanic na hydrovac ang problem, but I really appreciate sir yapoy's inputs (Im open in everyone's help naman po).
And logically speaking po, if hydrovac is the culprit, the 4 wheels will have the same problems, am I correct? But in my case, only the front mags and brakes are having issues...specifically, the front right side na laging umiipit ng husto ang preno.

TIA po mga gurus

[t2erns]

not specifically the piston, but yung kit na rubber na parang flat o-ring and the dust boot (parang accordion). and be sure na not grease ang gagamitin but either brake fluid or petroleum jelly. i'm not familiar with your car's brake but baka me posilibilidad nagkabaligtad ng kabit ang left sa right, the bleeder screw must be on top.

[gearhead000]

have you tried bleeding your brake fluid especially sa harap?

[basucat]

IMO, likely yung caliper pistons may deep scratches/rusting na sya. Even if they try to clean out the rust with sandpaper kung malalim ang scratches your pistons will stick (won't return to its original position) once it gets hot. To test if your hydrovac/brake booster works, step on your brakes while the engine is off. Start the engine and if the pedal sinks slightly, your hydrovac should be okay (this means that the vacuum created by your engine is able to activate the hydrovac). If it doesn't sink, your hydrovac is likely defective or the vacuum hose has a leak or the valve inside the vacuum hose is sticking. I am assuming that hindi ginalaw yung adjustment ng pushrod ng hydrovac. By the way, if you change the pistons, you should also replace the rubber boots (aka caliper kit). The boots keep the dust away from the brake system/fluid and prevents the fluid from leaking out.

[jick.cejoco]

from the write ups, my hunch is you have a nissan sentra. the system is a diagonal split brake system. the right front is paired with the left rear and the left front is paired with the right rear. your brake hoses are probably collapsed from age or improper service procedures. have both front brake hoses replaced. in the process, have the master cylinder overhauled or replaced. the compensating port in the mc might be plugged.

[sirkosero]

if that happened to me, wi'll just find another shop to have my car fix.

seriously, nung binuksan nila, hindi dapat linis lang. dapat overhaul the caliper and use a caliper kit. shortcut naman kasi ginawa ng mechanic nyo.

[miked]

suspect parts imo considering the age of your car and assuming no brake jobs before:

1. internally split brake hoses, could be due to old age or clamping the hoses before (pressure is contained and is not pushed back to the master cylinder when released)
2. piston seals worn out and lost its "spring action" (won't push the piston back to its released position)
3. master cylinders (rubber caps may be expanding and covers the compensating port when the brake fluid is heated)
4. proportioning valves/metering valves etc - might be out of proportioning action

brake booster is a remote possibility of locking up the front.

try mo na lang sa ibang service shops. wag ka na bumalik sa dati mo mechanic obvious na hindi sila marunong at gusto lang perahan sa back jobs.

[miked]

suspect parts imo considering the age of your car and assuming no brake jobs before:

1. internally split brake hose (pressure is contained and is not pushed back to the master cylinder when released)
2. piston seals worn out and lost its "spring action" (won't push the piston back to its released position)
3. master cylinders (rubber caps may be expanding and covers the compensating port when the brake fluid is heated)
4. proportioning valves/metering valves etc - might be out of proportioning action

brake booster is a remote possibility of locking up the front.

try mo na lang sa ibang service shops. wag ka na bumalik sa dati mo mechanic obvious na hindi sila marunong at gusto lang perahan sa back jobs.

[jick.cejoco]

don't forget the age of the brake fluid. if the fluid is older than two years or if the fluid has been exposed to the moisture in the air, the boiling point drops and it causes abnormal expansion creating pressure that makes the brakes drag

[PamelaAsistio]

Sirs, just an update lang po. I followed your advices, I brought my car in other shop and they overhauled my 2 calipers (again) then replaced a new caliper kit. Unfortunately, my 2 brakes are still having the same problems...kasi when I got home (its just about 10mins drive from the shop), hinipo ko ang mags at umiinit pa rin po.
Inadjust na nga nila un parang stick sa hydrovac na nagpupush sa brake master pero ganun pa rin :-(

[LN106G]

hi PA, your trouble seems to be not in the calipers. Sticking brakes usually point to air packets trapped inside your brake system. Causes are aplenty, the most common being inadequate bleeding when a mechanic changed some rubber seals (this is, if you had your brake's rubber cap or caliper kit changed before you had this problem), another is, since, your car is more than 20 years old (but still mechanically reliable as you mentioned), parts do breakdown, and I suspect the internal bore of your master cylinder became bigger due to wear and tear or the rubber seals (repair kit) of the master cylinder are worn out leading to "regurgitation" of the brake fluid to the reservoir and inviting air packets. With this condition, brake fluid can also leak back into the insides of your hydrovac causing havoc. Your mechanic adjusting the push rod b/n the hydrovac and the primary master is a BIG NO NO as this will disturb the Physics set by the manufacturer and will make your brake the more unreliable. Once this pushrod is touched, I assure you, your brakes will never be normal again. I suggest you change both your hydrovac and primary master with the SAME model and specs. Surplus is ok, but install a brand new repair kit (brands like SEIKEN, AISIN, ASCO, etc) for the primary master. Other things that you should address are the ff: 1- Change your flexible brake rubber hoses front and rear, 2- overhaul or change (if the insides are rusty, ragged or leaky already) the rear wheel brake cylinders, 3- inspect or replace defective proportioning valve or splitter fittings, 4- do a full brake bleeding after addressing all the problems mentioned above. Start bleeding your brakes from the farthest wheel to the nearest (from your primary master). 5- change brake fluid every 2 years, sooner if you wade your car in flood waters. Look for a mechanic who truly understand the brake system. Not to offend some out there, but, many "backyard" mechanics are mediocre when it comes to understanding the brake system

good luck...

[PamelaAsistio]

Causes are aplenty, the most common being inadequate bleeding when a mechanic changed some rubber seals (this is, if you had your brake's rubber cap or caliper kit changed before you had this problem)

Negative sir LN106G, the only parts that were replaced about a month ago before this happened...is the brake master kit, un pa lang po ang napalitan sa brake system ko last month. Yesterday lang po kami nagpalit ng new caliper kit.

By the way sir, are you sayin that my hydrovac is already busted and time to replace?
Its a bit pricey po kasi thats why we're starting to troubleshoot from the small things first, Im planning to replace my front brake hoses next week, isa daw po kasing factor yan sa present problem ng car, hopefully masolve na po after we installed new hoses...but eventually if the problem still comes out, I got no choice but to get a new hydrovac. Thanks

[batangtalyer]

Hi pamela, sa tingin ko nasa type ng brake fluid at bleeding procedure lang yan eh. DOT 4 ang pinakamaganda kase high temp yang fluid na yan. tapos sa bleeding sequence, yung rear wheel ang unang binibleed and make sure na wala ng bubbles ang rear bago mag bleed sa front wheel. and yung bushing sa gilid ng caliper assembly dapat nilagyan nila ng grease para ndi mag stick. - cheers

[LN106G]

[QUOTE=PamelaAsistio;1966263]Negative sir LN106G, the only parts that were replaced about a month ago before this happened...is the brake master kit, un pa lang po ang napalitan sa brake system ko last month. Yesterday lang po kami nagpalit ng new caliper kit.


Then that's probably where your problem started. The previous mechanic who worked on it must not have bled your system adequately. The most logical thing to do first is to rebleed your system properly starting from the farthest wheel to the nearest one (to your primary master). Try to observe the brake fluid reservoir while pumping your brake pedal, if it shows fluid regurgitation or bubbles consistently then your primary master is no good and you have to replace it. (this means maluwag na specified inside bore and even with new repair kit will not solve your problem). To know if your hydrovac is still ok, shut off your engine then pump your brake pedal until it becomes hard (if it does not become hard with several pumps, your hydrovac is no good), while steadily stepping on your "hardened" brake pedal, start the engine. Once the engine starts, notice if your brake pedal becomes softer while stepping on it and should stop a little midway through its play signifying a good and functioning hydrovac. This is one way of testing your hydrovac. But looking at your situation, your car being more than 20 years of good service, It is better to change your Hydrovac and primary master as one with the SAME model and specs. Your mechanic adjusting the push rod b/n the h-vac and primary master is a NO NO as this will create untraceable problem sooner or later. This I assure you. It is also wise to change your flexible brake hoses as well as service or change defective rear brake cylinders in one sitting to eliminate guesswork and will save you time and money in the long run. If your mechanic is knowledgeable, he will change them one at a time, bleed them one at a time, then doing a general "neurotic" bleed thereafter. A mechanic disassembling them at the same time will be inviting a lot of air packets and bleeding it will prove tricky.

BTW, a surplus hydrovac and master as well as flexible brake hoses are not that expensive.
Yes, they sometimes command a price, but, hey its your life that's on the line once you get inside your car...
cheers...

[jick.cejoco]

Negative sir LN106G, the only parts that were replaced about a month ago before this happened...is the brake master kit, un pa lang po ang napalitan sa brake system ko last month. Yesterday lang po kami nagpalit ng new caliper kit.

By the way sir, are you sayin that my hydrovac is already busted and time to replace?
Its a bit pricey po kasi thats why we're starting to troubleshoot from the small things first, Im planning to replace my front brake hoses next week, isa daw po kasing factor yan sa present problem ng car, hopefully masolve na po after we installed new hoses...but eventually if the problem still comes out, I got no choice but to get a new hydrovac. Thanks

the only parts that were replaced about a month ago before this happened...is the brake master kit,


if you changed your master cylinder cylinder repair kit, chances are the replacement primary piston cavity where the push rod sits has a shallower cavity than the original and the push rod is too long for that replacement piston that, since it is somewhat pushed forward while the brake pedal is fully released, the primary compensating port is being blocked by the piston and the piston rubber cap preventing brake fluid from returning to the reservoir. have the push rod adjusted with about 1 mm clearance or freeplay. do not replace anything yet that had been guessingly recommended by mechanic A, mechanic B, mechanic C and mechanic guess