Noticed today my brake master cyl has some seepage at a small 'hole' - see picture. I am not sure if there is supposed to be a bleed nipple or a block off bolt/rivet or something in there - can anyone compare theirs and let me know? My car is a ADM NA however the booster has a yellow 4WS sticker on it so it might be a TT item??? If you depress and release the pedal the hole will give a small "spit" of fluid and presumably suck in some air. Braking feels fine - I wouldn't have suspected a problem if I hadn't noticed the fluid you can see in the picture.
Need a rebuild, you're leaking between the front and rear plungers and it bleeds out this port. I've seen some with a grub plug in there, and some without.
I was afraid of this. I imagine replacing the grub screw/plug would eventually result in bad times. Given it would just fill with fluid / pop the plug. Repco/Bursons/ABS dont have a listing for the 90 300zx manual n/a - is there another car that has the same BM57 configuration? I will order one of these update: Ordered one direct from HFM rather than ebay https://hfm.parts/shop/brakes/hfm-bm57-brake-master-cylinder-abs/
The one I have purchased comes with a plug for the 'spare' front port. I did consider a rebuild - definitely. However a rebuild kit was quoted at $20 more than the HFM BM57 (express posted) that I purchased - then there is labor involved. My trunk monkey suggested the local guys who do the rebuilds are a bit hit and miss with sizing the right seal with the right bore... I will post back here if I have a bad time with the HFM unit.
Picture didn't load first time Swap that plug to the angled port closest to firewall. Those hard lines don't like being manipulated too much. Opposite here, rebuilds are usually better then a new BMC with SS sleeve.
I just took the BMC to a brake and clutch mob and asked them to rebuild it. Didn't cost much from memory.
The HFM BM57 turned out to be a dud - rear circuit is kill. will take my original to ABS and get it rebuilt -.- what a rollercoaster
Yeah, rebuilding and re-sleeving brake or clutch MC's are always the best option. Rebore and stainless sleeves make for a a significantly better live span.
Lesson learned. $70-100 to rebuild the stock unit. I am hoping HFM Dot parts will refund me given that the unit is faulty.
kill. caput. fanito. dead. broken. f&*ked. under normal pedal operation something between none and very very little fluid is pushed into the rear brake circuit. Testing the BM on a bench, pushing the cylinder in with a screw driver. Fluid is pushed out of the front circuit outlet in a fairly normal way and none comes out of the rear circuit at all until your quite a way through the stroke of the cyl. - at that point there is a small dribble of fluid from the rear circuit outlet. At about 95% full stroke there is a fairly decent squirt of fluid from the rear outlet however I would say its a 20/1 ratio of fluid ejected from the front compared to the rear (I didn't exactly measure this - that is a guesstimate) - this is very different to the stock unit. as mentioned - the HFM BM57 does not return all the way on its own - its like there is a spring missing inside or something... that combined with the fact that it isn't pushing enough fluid to the rears to even bleed them - tells me its been put together incorrectly.
note: HFM Dot parts had a faulty batch of BM57's They are going to refund me in full as they do not have an ETA on replacement parts from their supplier. Unfortunate. however top marks for HFM Dot parts for being good sports about the whole thing.
