99 v70 2.4 help with spongy pedal

[duckhunt]

Greetings, I hope you can take the time to read and offer some assistance,

It is a shame my first post highlights a stupid error I’ve made. I’ve worked on my cars for 15 years and have done brake jobs many times with ease.

For clarity I had the big clunk in reverse which I diagnosed to the handbrake shoes on the rear. So I set out to replace them. Sure enough, quite hilariously, upon removing the rear discs, the old shoes just fell out from the brackets. Anyhow I replaced them with new and adjusted.

Prior to this, while removing the rear left Caliper. I was obviously head in the clouds, and stupidly undid the 4 Allen bolts on the calliper instead of the calliper MOUNT bolts. So on loosening half the calliper I saw fluid pouring out. Hmm that’s a lot for the penetrating oil I put on. Oh it must be dot 4. Oh dear. So I quickly replaced the 4 bolts. I managed to snap the head off of one, amazingly. And continued the replacement of the shoes, which seems to be fine.

However, upon lowering the car back to test, the brake pedal is now very soft and travels to the floor, despite pumping maybe 10 times.

So I dared not take it out for a test drive. My driveway slopes down onto the road (with kids riding their bikes!)

My question is do you think I can resolve this by bleeding just that caliper? I have not bled brakes before but happy to get it sorted. I have ordered some dot 4 and a little bleed kit from Amazon next day delivery. Although I am well prepared to bus/cycle to work Monday. From what I understand air will be down there from the calliper coming apart.

I just can’t believe I was so stupid and didn’t stop to think whilst removing FOUR bolts from the calliper. Well we live and learn.

Please let me know what you think. Thank you.

[scot850]

It does sound like you have a lot of air in the brake circuit. How much fluid leaked out? If the brake fluid tank emptied, then it can sometimes be a devil to get the air out of the system as it can get trapped in the ABS unit.

A pressure bleeder is the way to go. Try bleeding the caliper you had the issue with first. If the bleed nipples are rusted, wire brush then and then soak with a decent penetrating oil (That does not include WD-40 which is useless).

If bleeding that caliper does not resolve the issue you will have to try bleeding the whole system (all 4 calipers). If that does not fix it then a pressure bleeder is the way to go or take it to a repair shop and have then do it.

Neil.

[duckhunt]

Thanks Neil,

I managed to resolve this by bleeding just the single calliper. I had probably lost around 100ml of fluid so not too bad. I used a little hand pump for around 20 minutes, topped up the reservoir and it’s all fine now thankfully.

I may need to adjust the handbrake again though. I always find this a pain. It holds the car on all but the steepest incline when I tested it. But I know over adjusting causes rubbing while driving. It seems quite unforgiving with the tolerances.

[scot850]

Tighten the adjuster on the rear until you cannot turn the rear wheel on each side. Then back them off 2-3 teeth, no more. Then adjust up at the parking brake handle end until you get 4-5 max clicks to tight.

Make sure both parking brake cables are working. Often people who have your issue with the parking brake find one of the cables is frozen.

I also recommend removing the rear brake rotors and make sure they are clean on the inside and not full of dust, which now you have cleaned them and replaced the shoes should be good.

Volvo had a process to bed the parking brakes in. It may be in the handbook I can't recall now. It involved putting the parking brake on and driving the car slowly for maybe 30-40ft to bed the shoes in.

Neil.

[foggydogg]

Welcome to the Tribe.
Sounds like you worked your way through the big part of the issue, but let me suggest putting a caliper on your shopping list the next time you're near a decent salvage yard. That broken bolt is liable to cause issues at some point.

[duckhunt]

Niel, foggydog,

Thank you for the guidance. As an update I did manage to get the handbrake nice and tight. It was only possible by 'bedding them in' by yes applying it gently whilst rolling along, I did this now and again over a couple of days, and then went to adjust it. It now holds firmly on the steepest inclines. I was prepared to swap them out for Genuine after reading other stories, but these are 'Mintex' and they are working fine.

Foggy, you confirmed for me what I have concerns over; a caliper held by 3 of 4 bolts, coming apart while driving and losing all fluid pressure. (Worst case?) I have had a used Caliper and new mounting bolts arrive, so I will clean that up and set out my first caliper change. Some questions as I can't find a DIY for the rear callipers;

1. The brake line is a rigid one, is there a way to 'plug' this once removed during the changeover or will I have fluid everywhere?
2. Should reservoir cap be on or off during the process?
3. I should 'prime' the new caliper with some dot4 before mounting, to minimise air?

Any guidance from someone who has changed a rear caliper would be great. I have a small hand pump bleeder only, which has worked for me already. I'm hoping to get this done asap to put my mind at ease.

Many thanks.

[scot850]

In the 'old' days I used to put a piece of cling film/Saran wrap over the master cylinder top and tighten the lid down which covered the air vent causing a vacuum and prevented most of the fluid leaking out the header tank. However, the modern unit have a float built into the cap to warn of low brake fluid. I had a spare cap and cut the float off to overcome this issue. I can only suggest in your case to try some cling film over the cap, leaving the cap off and try keeping it tight in place with a strong elastic band wound on tightly.

You can also try cutting a finger off a rubber glove and again putting it over the pipe end and pulled firmly (but not enough to split it) over the pipe end and again tying it with an elastic band tightly wound on. These days you do get clamp for flexible brake hoses that in theory you clamp over a flexi-hose (There is one just forward of the rear wheel on one side. (LHD is on the LHS rear, not sure if RHS is on the RHS?).

I am wary of using those clamps, especially on older hardened pipes for fear of permanently crushing the pipe. You could ask a local garage what they suggest. Other option is to pay someone to do it for you! Shouldn't be more than an hour's work.

The answer to your last questions are: 2) Lid on, 3) Hard to do but you can try using a syringe and opening the bleed screw until fluid comes out and then close it, keeping the caliper upright until fitted. The issue with that is if the connector on the pipe is tight, you may have to rotate the caliper on and the fluid may drain out in the process.

Neil.

[duckhunt]

Thanks for the guidance,
I have the new caliper all cleaned up with new mounting bolts ready.
I realised I did not have a decent flare wrench for the line, so I have one on order and I hope to tackle this next weekend.
That’s really helpful information.

[scot850]

Good Luck!

Neil.